1. Try to find a good balance for your mouse sensitivity and the control where you can shoot the exact same area consistently. Let's say the distance is from Avalanche: Allies 2nd flag to the fountain.
2. Change your cross hairs and see which is easier to see the exact spot where you want to hit them from. For me, I use the X, colored gray.
3. Look at your ping, compare it to others. Most people don't know this, but it can help you decide when and whereto shoot. If your ping is lower than others, you read the game faster than they do and have an easier time seeing them before they see you. If your ping is higher than others, most likely they will see your head before you see their shoulder. Depending on the difference.
4. Never lie prone unless you are on higher ground, or in a dark area. Sure the breathing control (figure eight when you are pointing) becomes easier, but if your body is wide open, easier to kill you.
5. Switch your weapons to quick swap. So all you have to do is press a number instead of number then click. Good way to change to melee when needed.
6. For the K98, K98 sniper, and Springfield, you can lessen the lag time between each shot by switching weapons back and forth. You'll notice your firing rate become just a bit faster. Scope, shoot, Q, Q, ready to aim. You won't see the animation of you cocking it again. It's just like in CS with the Scout and AWP.