On the map Kashyyyk: Beachhead, select the Galactic Republic and spawn in as a Clone Sharpshooter in the forward Command Post. Then, commandeer a BARC Speeder bike and race across the water. Quickly get into the nearest enemy STAP. Speed back to the forward CP and go up the ramp and on top of the pointy building. Use the speed boost to jump the building like a ramp and up onto the three platforms. From there, just snipe away until you run out of ammo. Know that upon impact with the roof of the platform will cause a serious damage to your vehicle.
Note: You may be able to use other vehicles, but STAP's are the easiest. Also, this trick works best if you are either the Clones or the Imperials. If you use it as someone else, the other team will send a Jet Trooper or a Dark Trooper to quickly get up there and kill you.