When performing a bombing run, keep checking the mini-map to see all enemies. Any enemies standing outside the shelter will appear there. Although you may miss bombing a few enemies grouped together at their base, it is better to kill campers outside the air raid hut.
After spawning, fly a plane directly to an airfield base. Parachute out and immediately capture that base. This will allow your team to spawn at the strongest point and also unlocks the bombing run, tanks, and another plane.
You usually will not get points when using a sniper from within your spawn point. However, the anti-aircraft area on aircraft carriers are not treated the same way. You can remain in the gun area and get points. This is especially useful on Iwo Jima when attacking the Lighthouse or Beach.