Hint - Stowage Problem
For the Xbox 360, don't forget to select a storage device and a gamertag before embarking on a New Game. LEGO Star Wars 2 will not notify you about not saving any progress once you start playing without selecting a save data destination.

Hint - Double Score Zone Exploit
Double score zones allow players to gain double the credits from studs. Because of that weird effect, you can exploit it by killing your partner (2 active players only) and taking his money (and vice versa). While you lose a set amount of money, you also gain double that amount because of the double scoring effect.