Im practicing with the jet trooper right now so i suggest...
If youre in a level like mos eisley with buildings everywhere and there are small passages then use the jetpack to fly to a large group of enemies throw a grenade and fly out. It does massive damage.Also in mos eisley you can take the harbor(or whatever its called)really early on by flying above the walls where the droids leave. Theres absolutely no security on the top of the wall but sometimes theres a gunner on the ship so watch out for that. Only use the EMP Launcher against droidekas. Even if they have there shields up use the EMPs any chance you get. Unless fighting against a droideka use the blaster pistol. The jet troopers blaster pistol is more advanced then other clones pistol with a much faster rate of fire. If you know how to tap a button repeatedly really fast then that little pistol should act like a blaster rifle. In case you dont already know this when flying the jetpack to fly up look up and to fly down look down. Same with going level. Look straight ahead. One major advantage to using a jet trooper is that no matter how high he falls from he doesnt get hurt. That really comes in handy. Im really getting pretty good with the jet trooper so if yu need any more tips then just tell me.