Basically put everything else besides apps on the SD card. Mostly photos, videos, and musics like Snipergod said, or other stuff such as documents or things you don't need. Don't install apps on the SD card, plus I don't even think lots of phones can do that anyway (with the exception of rooted phones). You might want to get at least a class 10 SD card, they aren't that pricey, and you get performance.