I've been answering a few questions regarding deck building on this sub-reddit and found that I'm repeating myself a lot. So I decided to put them into 1 thread for everyone to find and reference for tips on building decks.

There's a specific way I like to build my decks that make it much easier to keep track of upgrades and what-not. I'll go through this process step-by-step, using my Sparrow deck as an example.

First thing's first, choose your prime card. This is quite straightforward. The Archmagus is for energy damage, The Warlord is for physical damage and The Centurion is for health. This is the card that activates when you get the OP buff from the big purple dude. For my Sparrow deck, I'm going to pick The Warlord, since Sparrow uses physical damage and as a carry health is not really important

Second thing's second, add in a Health Potion, Mana Potion and Harvester's Key. These are auto-includes in every deck, you may not use the Harvester's Key much with you character but it doesn't hurt to have it there, just in case. If you choose not to take Harvester's Key, consider a Scout's Ward instead.

Now the fun stuff. We're going to add 4 equipment that will make up the core of our deck. Select the 'Filter' button at the top and choose an attribute you would like to focus on, mine will be Physical Damage. Look through the selection of equipment you now have with your main attribute, and find a good secondary attribute, mine will be Attack Speed as Sparrow is reliant on her basic attacks. So I add a Windcarver Blade to my deck.

Basic attacks aren't that great without a bit of Crit Chance, so let's also add a Spear of the Rifthunter (Physical Damage and Crit Chance).

Continue in this fashion until you have 4 equipment with your base attribute and a relevant secondary attribute or active ability.

These equipments aren't going to do us much good on their own, so it's time for upgrades. Upgrades can only be applied to an equipment that shares the same attribute. For example, a Major Strike (Physical Damage) can only be applied to equipment with bonuses to Physical Damage.

Note: Attribute bonuses in the 'Fully upgraded bonus' section of the card do NOT count. A good example of this is Chronospike, which has bonuses to Max Mana and Physical Damage, with an upgrade to Cooldown Reduction when it's fully upgraded. You can't put an Advanced Chrono (Cooldown Reduction) on a Chronospike.

A good tip is to select your equipment in your deck list (The list on the left, not the cards in the center) and select 'Filter by', this will only show you upgrades that are compatible with that equipment. For each of your 4 core equipment, select 3 upgrades. Once you've done that, your core build is finished! But we're not done yet.

It's time to add 'Flex' equipment. These are equipment that share the main attribute with one of your core items, but has a different secondary attribute, or perhaps an active ability that you may find useful in certain games.

If you're confused by what I mean, I'll give an example. My Sparrow deck has 2 Windcarver Blade (Attack Speed and Physical Damage). For each of these, I have 1 Major Kinetic (Attack Speed) and 2 Major Strikes (Physical Damage), both of these Windcarver Blades are core equipment in my build. After playing a few games with this build, I've found that some games I only get 1/2 hits on someone before they disappear (dammit Kallari.) so doing some extra damage with those 1/2 hits would be better than having extra attack speed, perhaps some Crit Bonus? So I put in a Blade of Agora (Physical damage with Crit Bonus on fully upgraded) as a replacement for Windcarver Blade when I'm in a game against a team with a Kallari.

Another example (bear with me, this is important) would be if I wanted some Max Mana instead of Attack Speed, because I'm lacking a bit of sustain during those longer team battles, the enemy team composition has a lot of health and escape so the battles drag on. I would put in a Fountain Spike (Physical Damage and Max Mana) as a replacement for Windcarver Blade.

Now, I only have 2 upgrades for my Fountain Spike since Major Kinetic (Attack Speed) isn't compatible with Fountain Spike, so I add to my deck a single Advanced Mana. There is no need to add in 2 Major Strikes (Physical Damage) for the Fountain Spike, since it will be replacing Windcarver Blade and therefore can use the Major Strikes I added for that.

Once your flex items are in, and have any relevant replacement upgrades, your build is done! Play with it and make note if you're ever lacking a certain attribute, you may have room for more flex items in the future.

My Current Sparrow Deck:

Prime:

• The Warlord

Auto-Includes:

• Health Potion (1)

• Mana Potion (1)

• Harvester's Key (1)

Core Equipment:

• Windcarver Blade x2 (3) (Physical Damage, Attack Speed)

• Spear of the Rifthunter x1(3) (Physical Damage, Crit Chance)

• Blade of Agora x1 (3) (Physical Damage, Crit Bonus on Fully Upgraded)

Core Upgrades (In order of equipment):

• Major Kinetic x1 (3), Major Strike x2 (3)

• Zealous Wound x1 (4), Major Wound x1 (3), Wound x1 (2)

• Major Strike x3 (3)

Flex Equipment:

• Lantern of Spring x1 (3) (Energy Pen, Physical Armour, Cooldown Reduction)

Note: Energy Pen does nothing for Sparrow, since she is a Physical Damage character. Sometimes you have to just make do if you don't have the exact card you want, I wanted Armour and Cooldown Reduction, this is was the best item I have available to me that matched that criteria.

• Fountain Spike x1 (3) (Physical Damage, Max Mana)

Flex Upgrades (In order of equipment):

• Advanced Chrono x1 (3), Chrono x2 (2)

• Advanced Mana x1 (3)

Best of luck to you friends. If you have any questions feel free to post them, I may add the answers to this post for others :)

EDIT: Formatting large posts isn't very fun.

EDIT 2: I was asked to post this guide on paragon-game.com, instead of copy-pasting I decided to extend in, fill in the gaps and format it better (Reddit's formatting leaves a lot to be desired). You can find this extended guide here: http://paragon-game.com/build-guides/a-complete-guide-to-deck-building