Unnecessary Preamble:

Hey Y'all! I've learned a good bit about how to properly setup a guitar, and would like to share some of these pearls of wisdom. As a person just getting back into playing guitar after years away, getting string action and clean fretted notes has made a world of difference in making progress and being proud of the tone I can create. Strings that hang low over the frets, but ring like a bell are the difference between hitting notes easily and climbing on the metaphorical monkey bars at the playground of misery. Fair warning, I am going to link to Sweetwater for some of the things I mention because they've been great to me with support and free shipping. I make nothing from these links and am not an affiliate. If anybody has a better at home method than what I suggest below, please don't be shy about it. I will make any edits that make sense to improve this information. Without further ado, lets get to it!

Essential Tools (picture):

• Digital tuner (you should already have a pocket, clip on, or stompbox one if you are even halfway serious about guitar)
• String action gauge
• Metric allen wrenches from 1.5mm to 6mm size
• Lil baby screwdrivers from the hardware store. You may need both Phillips head and flat head depending on the screws on your bridge.

Basics Of String Action & Intonation:

Neck Relief is the slight curvature of your neck that you absolutely need to have cleanly fretted notes up and down the entire fret board. If there is not the ever so slight curvature allowed, your notes closer to the headstock are likely to buzz and impact the clear ringing sustain every guitarist desires. Often guitarists will mistakenly increase the height of their bridge saddles to fix this, which is a good way to be swinging from the metaphorical monkey bars I mentioned in my opening. There is a delicate balance between the amount of relief you have, and your bridge saddle heights. I will go over this in the 'Truss Rod Adjustment' section of this guide.

String action is the height from the bottom of your strings to the top of the fret. At the simplest level, how high you have the strings creates a trade off between easily fretting notes versus having more clearance on fretted notes which gives a guitarist more room for bending notes as well as using more dynamic (high and low volume) picking. For most people, they like the action "low", which in measurable terms is less than 0.080 of an inch in action. Personally, I've found a sweet spot of about 0.070" on the low E string and 0.60" by the high E string. Across the fret board, most guitars are able to get 1 to 2 hundredths of an inch lower action going to the thinner strings. Getting this right is tricky because you must contend with both how much the neck relief raises the strings off the fretboard, as well as how high the bridge saddles hold the strings. Its a bit of a trial and error process with your at home tools. This will be discussed in the 'String Action Adjustment' section below.

Intonation is the degree to which notes are in tune up and down your fret board. This is dictated by the length of your strings from nut to saddle, and can be impacted by not only the distance the saddle is screwed longer or shorter, but also how tall you position it. Also throw in the curvature of your neck relief, and that further complicates the ability to stay in tune on the fret board. At their hearts, guitars are imperfect instruments, and its impossible to have perfect intonation on every fret. Therefor guitarists will adjust their saddles to achieve the best intonation at a specific part of the the guitar they spend most of their time. For simplicity, I will discuss correct intonation at the 12th fret below in the 'Adjusting Intonation' section below. Not all guitars will need truss rod or string action adjustments, so it would not be a high crime to skip down to this section.

Truss Rod Adjustment

This may be the most daunting of all tasks in terms of fear of messing up your guitar. I personally feel that it is the right starting point to get your action and clean fretting in order It's rather easy to access the truss rod adjustment bolt on Fender type guitars, but often requires you to remove a truss rod cover on many other guitar brands. Hiding in that little nook is a bolt end that will accept your allen wrenches. Depending on the truss rod used, it will likely require a 4mm to 5mm wrench to make these adjustments. Make sure you have the 4.5mm size also because you don't want to round off the bolt if you don't have exactly the right size.

Here is a picture of my Fender Nashville Telecaster's fretboard where you can see the ever so slightest inward curvature (focus on the line created by the fret ends). This curvature allows notes on the lower frets to ring true even though they are so far away from the raised bridge. since the height of the bridge does little good 22 inches away, the curvature does the heaving lifting of getting your strings far enough above the next fret to ring clear and avoid buzzing.

My picture above is an example of about the right amount of ever so subtle curvature you want to aim for. Tightening the truss rod bolt will make the neck flatter, while loosening it will make it more curved. IMPORTANT NOTE: you do not want excessive curvature/relief or it will in effect shorten the scale length of your guitar, and make it impossible for you to get good intonation down the fretboard because the frets will simply be in the wrong place relative to the scale length.

Steps

1. Tune all six strings to your specifically used tuning. For most people this is EADGBe
2. Eyeball your fretboard to see if your truss rod could use some tightening or loosening
3. Now loosen your 3rd and 4th strings with a few turns
4. Lift the strings out of their slots in the nut and slip them over to sit on the 2nd and 5th string nut slots respectively over those strings
5. Now use the allen wrench to make a marginal adjustment of a half to a whole turn at first if way off. Consider only quarter turns if you are close.
6. Put your 3rd and 4th strings back in their nut slots and re-tune all 6 strings. They will all be out of tune due to the change in neck relief making the scale length marginally shorter/longer
7. Look down the neck for your ballparked level of relief
8. play notes one fret at a time up to about the 7th fret on each string to check for buzzing (if you are satisfied with the curvature/relief you have in the neck
9. repeat steps 3. through 8. until you get notes that ring clear at each fret on each string. You may have to come back and adjust the truss rod again after raising/lowering your bridge saddles... its just the nature of the beast since action is dependent on both the relief/curvature and saddle height.
10. It is not uncommon for the neck relief to relax or straighten out further over the following days after you have made the adjustments. Keep an eye on your action and adjust the truss rod as necessary once the neck settles in.

String Action Adjustment

Now that you have gotten your truss rod and neck relief sorted out (at least for the moment), the next step for you, our handy guitarist, is to break out the string action gauge and figure out how high your strings are. More than likely, if you are like many people that have come here genuinely hoping to learn something, you have just raised your bridge saddles to monkey bar level to fix fret buzzing issues. Now is your chance to bring those saddles back down, and get a much more comfortable string height at the 12th fret (middle of your guitar's scale length!). The instructions I'm providing here are for electric guitars, since most acoustic guitars have a set bridge which cannot be so easily adjusted. I claim no extensive knowledge in adjusting acoustic bridges, but understand that sanding the bottom of the bone bridge inserts is how its done (go look online, I am not your guy!). Anyways, back to the electrics, if you want low action you should be shooting for a string height on the low E that is between 0.090" and 0.060". Personally, I like 0.70" on my guitars because its my sweet spot that allows for a wide enough range of picking dynamics while also feeling really comfortable. IMPORTANT NOTE: Not all guitars will have a perfectly dressed and leveled fretboard. If you are unable to get the strings this low, you might consider going to your nearest luthier to have them level and dress your frets. If your frets have extensive wear, this may require a new fret job. For set neck guitars, sometimes it makes more financial sense to just buy a new neck that you can toss onto the body.

Steps:

1. Get your guitar in tune and pull out your handy dandy string action gauge card
2. Check your action on the low E string by sitting the gauge on your 12th fret like this
3. adjust the height of your individual saddles, or low string side of your bridge assembly to raise/lower the height accordingly till you achieve your target height. If you have a tune-o-matic fixed bridge style, I strongly suggest loosening all strings significantly before turning the bolt so it does not damage the screw slot.
4. re-tune your string and play notes from the 12th all the way up to the last fret on your board. We want to have clear ringing notes. If you detect any amount of fret buzz, the bridge/saddle should be raised marginally.
5. If you are unable to get your string action as low as you would like before the frets buzz, this is a sign that you may need to go back and further adjust your truss rod. If this is the case, go back to the 'Truss Rod Adjustment' section of this guide and go through the necessary steps to slightly tighten your truss rod down more. This will lower the action at the 12th fret, but make sure that you can still play clean notes up to the 7th fret!
6. Once done with the current string, go through each successive string across your fretboard to achieve the desired height/action that feels comfortable. The jump from the wound strings to the unwound strings typically allows you to jump a full hundredth of an inch lower in height. You should be able to have each successively higher string ever so slightly closer to the fretboard, but its not a requirement.
7. If you have a string action height that satisfies you on all strings, and all the strings ring clear up and down the fretboard, give yourself a pat on the back. the last half hour was well worth the careful tweaking to improve your comfort with fretting notes and chords!

Adjusting Intonation

Congratulations for making it this far, you are quite nearly done. The heavy lifting is out of the way and you are almost done. For all that is good in this world, don't skip this step. This is truthfully the most important part of your tone. If your guitar is not in tune beyond the openly played notes, its going to be very annoying to listen to and be heartbreakingly frustrating to your ears. The good news is that adjusting intonation is a pretty quick and simple task relative to the last two labors of love. All the truss rod adjustments and string action raising/lowering have ever so slightly pulled your intonation off from ideal at the 12th fret where each string's open note should be the same (E open matching E 12th fret on the tuner, A open matching A 12th fret on the tuner, etc.). IMPORTANT NOTE: Every string needs to be gradually different in length to be perfectly in tune. I don't understand the science personally, just understand that its the reality of it. Also, the G string is a bit of a joker and has to be a good bit further back than the D string just before it.

Steps:

1. Once again, the reference point will be my nashville Tele which has phillips head adjustment screws. If you have a tune-o-matic style fixed bridge you will likely need a flat head screwdriver. Make sure your strings are in tune
2. First step is to strum your open note on the low E string, then play it again at the 12th fret.
3. If the note at the 12th is sharp or flat, you will need to adjust the saddle of your bridge, loosen the string.
4. If the note was sharp at the 12th, you will now use your screwdriver to make the string longer with the saddle. If the note was flat at the 12th, you will now use your screwdriver to make the string shorter with the saddle.
5. Retune your string and check the intonation again by playing an open note and a note at the 12th fret.
6. Repeat steps 3. through 5. till the string you are on is perfectly in tune at the open and 12th frets, then go to the next string

You Are Done, Congrats!

This little guide is the culmination of what i have learned as a new guitarist scouring online resources and putting the processes to the test myself. I fully appreciate that my methods may not be the same as yours, and if I've suggested something heinously out of step with good guitar maintenance, let me know! Best to you all and enjoy your now greatly improved guitar!