Key Setup:
These are a couple of my methods that I use when playing. First off, I set my key set-up to WASD. W=forward, S=backward, A=strafe left, and D=strafe right. Then I set the Space Bar to jump, and C to crouch. My left mouse button is fire, right click is alternate fire, and the scroll wheel has no purpose other than scrolling (I have found that I accidentally alt-fire to much when I used the scroll wheel button).
Weapon Setup:
Now I want to go to Weapons. Everyone has certain guns they like and are good at, but I have found a trait in most old-time NABers. They all know how to use the Hyperstrike. I once game I had with Sk8er in PM-BattleChessRemix.nrf. I would warp in on one side, and go to attack him. But no matter how often I tried I always was stopped by his Hyperstrike. After that game I started practicing with the Hyperstrike. I have seen some players that didn't like the Hyperstrike start practicing with it and actually start enjoying it. But, of course, the Hyperstrike has advantages and disadvantages like any other gun. The good is that it doesn't use as much ammo as the Triplestrike, it is more accurate than all the other guns, and it has a scope for long range shots. The bad is that it isn't able to get area kills, its sights are off, and if you don't have good ping (or the person you are fighting doesn't have good ping) it can be very hard to fight. The Scatter Shot is also a very nice gun. It can take people out with 1 shot (no need to use alternate fire with this gun). The problem with the Scatter Shot is the long canister changing time and the short range.
Here is my listing of weapon priorities:
Hyperstrike
Scattershot
Triplestrike
Pulsator
Wildfire
Ballzooka
Sidewinder
Nerf Cannon
Secret Shot II
Whomper
Game Play Tips:
Now It is time to move on to game play tips. First off, do you like waiting 30 seconds on the standard maps? Well you won't have to wait any more. All you do is press the Tab key then type suicide. That will knock you, thus allowing you to move free after you re-spawn. This tactic is impractical if you only have about 10 seconds before the game. If you think the suicide code is cheating you can always use the crouch method. Press C and move in the direction you choose. You can even move up stairs by that method.
I have covered all my basic pre-fight tips, so I will move to fighting tactics. Try not to get into a fight with someone who has the Triplestrike when all you have is the SecretShot II. Use your strafing keys as much as possible. I recently had a fight with Ace[CD-S] and I saw that he used double tapping of the strafe keys constantly. It made it very hard to hit him (by the way, he was also good with the Hyperstrike and Scattershot). You can also use double tapping of your strafe keys to get across gaps if the ceiling is low.
That pretty much covers my basic tips. Hopefully I will be able to add more stuff later.
Field Of View:
Setting your Field of View to a different number than the game default can give you an advantage. All you have to do is when you are in game press the TAB key and type FOV (put your number here, default is 90, I am using 120).