Call of duty kill streak help?

I play a lot of Call of Duty MW2. I am not bad at the game i am simply looking for some pointers. Usually in game i use kill streaks like UAV,Harrier, Chopper gunner. these killstreaks work good for me but i want to get my EMP emblem and its a little more difficult to from harrier to EMP anyone have any ideas on killstreaks that might work a little better?