Generally, pictures and music cause the most size problems. If you have a lot of sounds, get a sound program (like Audacity, which is free) and change the recording rate to be a lower amount. Not many can hear the difference between 44.1 and 22.05 or even 11.025 (which can cut your size down in half or fourth for the sound piece). If pictures are the issue, try to open the pictures in a program like Paint.NET (another free program) that will auto-detect the minimum needed space required to save the picture.