The element of surprise
Being unpredictable in First Person Shooters
There's no better way to get kills. When you catch your enemy by surprise you have complete control of the fight. If you attack your opponent while your location is unknown to them, you will have the advantage of superior reaction time. Even the fastest of players will not be able to react to a player half as fast as them if caught by surprise (assuming you can hit the broad side of a barn of course).
Choosing when to attack is what good players understand and what bad players don't. Even if you can't aim at all, if you have the element of surprise, you should control the fight. Just because you heard someone run by, doesn't necessarily mean it's time to strike. You need to consider the position of your team-mates, how many potential opponents you'll run into, and whether or not you'll be out-gunned through firepower or flash-bangs. Don't jump into a situation unless the odds are stacked in your favor.
Learn some of the best spots
A very common, but good example would be the large crate in bomb-site B on Dust2. It provides plenty of cover, room to move around after the Terrorists have entered on a rush, and is a great place to counter-flash. If you wait for them to come to you, they won't know what hit them when you bounce a flash off the wall.
Don't repeat your actions every round
Being unpredictable requires that you and your team to change up your tactics. If you just completely steamrolled your opponent by rushing at a certain place two rounds in a row, it's a good bet that they'll be ready for you by the third round. On the third round, it's much better to try and rush a different site, but lead your opponent to think you're doing the same thing again.Eg: Toss something like smoke grenades where you rushed the first two rounds and on the third round, toss the smokes, but charge the other site. When the dust settles your opponents will probably have rotated or stacked the first site, while you're bomb planting in the other.
Don't bait, unless it's the enemy
Now although baiting will land you more kills, it will also put your reputation in the trash. If you're baiting your team-mates, you'll be looking for a new team pretty soon. Rather than baiting your teammates, work with your teammates and bait your opponents. You can do this by telling your teammate to agitate the enemy through gunfire while you hide in a inconspicuous spot. When your opponent(s) come charging in to kill your teammate, jump out and kill them before they get to your teammate.
Play smart defensively
As most players know, peeking in matches against good teams gets you killed. Instead, setup a crossfire with your teammates and learn how to play spots to surprise your enemy. Don't sit in the same spot every round. If your position isn't working stop using it, move around a bit, or even push(rush your opponent). The best players are always changing up their tactics. Even if you have poor aim, if you know how to surprise your enemy, you'll be one step closer to "becoming a God at First Person Shooters".