I jumped up my once terrible KD up to 1.25 in just 2 months (been playing since release) by switching to HC SnD; I love the rush! I have no idea where to start so I'm going to just jump in:

I run SCAR silencer, pro stock, long range frame, FMJ, 3.0 V optic. RPG. Cold blooded, hardline (everyone only dies once, kills & streaks therefore take longer to get to), and tracker is king in HC SnD, Thermite, & Stim for me. UAV, Pmissile, VTol

I don't waste a kill streak on a UAV Jammer; so I just go with FMJ and can easily take out the enemy UAV in 4 shots.

Silencer is a must have

Dead silence is a staple in this mode. Period.

Other Staples I've Learned:

If you're at a window, STAND/CROUCH AWAY from window edge, your barrell WILL GIVE YOU away and get you killed.

Crouch is king. If you're heard, you're likely dead soon.

Have a plan. Not just out the gate either. For example, if you're on Defense and you go to defend B, have a plan if your team at A starts getting picked off or enemy plants at A. MOVE YOUR ASS.

HAVING A ROUTE IS HAVING A PLAN. Know where you're gonna go, the more you go to your "routes" the more you'll know where you're likely to run into an enemy.

Have head phones or volume up high. Be somewhere quiet (in your home). You AND your teammates NEED to be able to hear enemy footsteps. Its simply essential for HC SnD

Defense: UAV can be saved for offense, unless you're alone and think you have a real chance of clutching.

Clear areas in sweeps/stages. Take Grazna Raid Defense for example, usually, i go B slowly creep up stairs zoomed in at tank (this is the closest 1st place you may see an enemy). Clear. Now move to upper windows only (maybe they got up the tank quicker than i zoomed). Then lower blue house, ending at bottom left most side of blue house.

Then I move up the stairs check trenches etc. Then i watch the back of B checking as far right as i can, periodically checking right and left.

If i see the team getting picked at A, i clear everywhere quickly and make my way there. Why wait for the enemy to plant?

Which brings me to another point, dont get stuck on your "spot". Your run and gun teammates need you to step up if they get killed.

If you see smoke, HIDE unless you have thermal. Wait for the smoke to clear to scan for enemies.

Don't be afraid to hold up. Its on the enemy team here to make a move. Chances are, you've got solid run and gun teammate clearing the others areas. HAVE THEIR BACK if one gets by them and stop the plant. Be ready to move if you're team dies.

Know your time. How much is left? How long does it take to plant, explode, or defuse.

Offense: UAV's are more valuable here.

Make sure half the team goes with the bomb. Don't be the one who doesn't pay attention. Cool you got 3 kills? Well you got 30 seconds and you're 1 v 3 and the bomb is 100 meters away. Not ideal. Just back up the homie with the bomb.

With that said, if you go with the bomb, your important time is at the begining. WAIT for the enemy to overextend FIRST. Pick them off. At this point, dead enemies are likely reporting your LKL aka your Last Known Location. Which brings up another point:

Move after every kill if possible. Not a whole lot, but enough to NOTZ be where they know you are, but close enough to pick off the guy sent to avenge his dead teammate you just killed.

Move up as a unit, together. One looking one way another covering the other. After you're deep into the match, check your 6! DON'T GET FLANKED. Pay attention to who went in what direction so you have a general idea of where a teammate died in case they cant report it (no mic).

If you die, don't keep going back round after round just handing over yourself to the enemy team. As Albert Einstein has said (paraphrasing) don't do the same thing over and over and expect different results.

WATCH THE BOMB. No point in planting if they defuse. The enemy as to COME TO YOU once the bomb is planted. If you're not near the bomb when it planted, DON'T stand around forever, BACK UP THE BOMB SITE. Protect it. Even if you die, if you delay them long enough (with a gun battle or a thermite) you can still win, even if you're dead.

Lastly, in my humble opinion, don't bitch about camping, EXPECT it. This is HC SnD. If you're on offense, expect there to be campers defending the bomb sites. You KNOW where they will be, KILL THEM!

Side notes: If you call in ANY Kill streak that can kill teammates if they are near, give them a heads up and make damn sure to avoid them. Your VTOL is USELESS if its first 2 kills is your teammates!

My strong suit isn't running and gunning, but I've 1v6 1v5 and clutched the win many times. I'm not afraid of it, but I focus on my strong points to help support my more aggressive teammates. I have a big tv and sit close so I get many many long range picks. I use 3.0x zoom because it doesn't produce a sniper mirror. I use to run M2 Carbine but in HC it isn't necessary and definitely isn't helpful if you've gotta step up and run and gun.

More often than not, I am well over 2.0 KD about 70% of the time, 20% just positive, 10% I encounter better players or have a shit team and do poorly.

Finally, I stick to the places I know best and am good at, but if I notice an overload of players in the same area or another good player going to my area, I go to plan B. Don't double up, be ready to let someone else have it for a game.

Much love for HC SnD players, my favorite game mode! See you on the battle field!