Tilt to avoid collisions and debris above you marked red exclamation points. However, there is a glitch that will have you repeatedly collide with a small building. If this happens, restart the game.
Avoiding soldiers while parachuting
Remain in the center of the screen as long as possible. This may be difficult at first due to the tilt controls, but with some practice it will become easier. If you fail you will restart the dive at a checkpoint, and not at the very start.
Rescuing survivors
Once on the ground, use the on-screen indicators to follow the path to survivors. Shoot to break through obstacles and not at Godzilla. Rescue the survivors then exit as fast as possible.