Ways of exposing enemies
There are several ways to know where an enemy might be.Pay attention to the signs during gameplay and expose the enemy.
Recon is a very useful perk as every enemy that takes explosive or bullet damage is marked as a red arrow on the radar, which also shows the direction the enemy is facing.Be one step ahead!
You can see the area that an enemy is, by locating the drop area of the care package he calls.Many times though there might be a trap with a booby traped care package so this doesn't work all the times.Be cautious and proceed.
Another way to get help is the recon drone.If you or one of your teamates calls the recon drone,the whole team might learn where all the enemies are.
Some times sitrep might help you expose an enemy.Sitrep gives you the ability to see all of the enemy equipment.If you are searching an area that don't have anything blinking and suddently you see an enemy claymore or any other equipment deployed at that time ,then an enemy is there and is preparing for camp or setting his traps.This is most useful at the begining of a round where enemies preparing their defences.If you are a quick rusher you might have the chance to see something like this.
Marksman is very usefull perk as it allows you to identify enemies from farther away by showing their names at a greater distance.You can see enemies that in any other circumstances you wouldn't be able to see.
Teamspeak or any other program that allows you to communicate with your teammates is a big advantage for you and your team.It allows you to exchange information realtime ,to learn where an enemy might be and to avoid unecessary actions.
Killstreaks as uav and advanced uav might give you great help and provide you with the necessery intel in order to accomplish your goal.