Mode: Battle Enemies
Enemies: Battle Droid, Battle Droid (Commander), Droideka
Get to a circular are that you can walk around, as you destroy enemies. I've found that in circular/long areas which you can walk back and forth/around, enemies will spawn (by the falling from the sky) more quickly.
Mode: Collect Studs
Keep an eye out for purple studs and powerups.
Mode: Stud Hunt
Hunt: 147,000 Studs
In this level, it can be a little hard to move different levels in the map, as there aren't many clear grapple points (a lot of them are hidden underneath containers or plants). Instead, look for lifts to go up instead.