Begging At Dexters: Dexter's Diner, where you select your stage/missions is a veritable loot heaven. Your characters never lose money if they die at Dexter's Diner, so each time you complete a stage, walk around the place with any Jedi character and force pull studs from all the objects around the hub level.
Cheese-Kill Anakin Skywalker: In stage 3-6, have a second player take control of the boss and force the character to jump over the lava pit. Just before Anakin Skywalker hits the lava, have the second player hit pause and drop out of the game, resulting in the AI taking a hit. Keep repeating the process and you can force an easy win. Pun intended.
Switch Hitting: Freeplay (or Free Mode) is best for exploring previously cleared stages for studs and minikit parts. A preset "cast" is selected for a particular stage or mission which allows a player to access all the doors previously missed in Story Mode. Use the L or R keys to cycle through the cast while playing on free mode.
Unlock superkit: Unlock the superkit (the big AT-TE model outside Dexter's Diner) by filling the Jedi bar while playing. Filling the Jedi bar is not a simple function of money, but also in grabbing all the pre-staged LEGO studs in each mission. In vehicular missions (particularly the pod race), the player needs to smash and destroy all the destructable objects to gain money.