At the start of the game, run though the back door to a gun faster and safer than going to the man at the front. Hit him in the head and he will die faster.
Better Sniping Accuracy
When in sniper mode, zoom in. To steady yourself for greater accuracy, sit there and do not touch anything to look or move for about five secounds or until he stops moving around. You can now look around with perfect dead aim accuracy.
Wait until an enemy reloads his weapon before killing him. Kill him before he fires his gun and you will get a full magazine for your weapon.
When you first start the FBI level, immediately after the woman shoots out your cuffs, go to the center of the room with the three computers. You will find the Ubisoft logo acting as a screensaver.
In Multiplayer, Create a fight. You automatically begin with the 9mm. Hold this weapon. It haves maximum 13/0 Bullets, you see that at the bottom on the screen. If you shoot once, it will change into 12/1 , you can also shoot all the bullets out, then it change into 0/12. If you press A reloading the gun it has 13/0 again!