Launch iTunes and tether your iOS device to your computer. Allow it to sync normally. Now, locate the icon representing your device on the left side of the iTunes window. Click it once with the mouse to select it.
Now note that you will see a picture of your device as well as a series of tabs. The tabs are: Summary, Info, Apps, Music, Movies, TV Shows, Podcasts, iTunes U, Books and Photos. You can go to each of these tabs and manage the content of your iOS devices.
Click the word "Summary" on the tabs list in iTunes. Now look at the Options section. There are three options that will help reduce the content synced to your iOS devices. They are: Sync only checked songs and videos, Prefer standard definition videos, and Convert higher bit rate songs to 128 kbps AAC. Check any of these three to start saving space on your devices.
However, please note that in order for Sync only checked songs and videos to work you have to go your music and video libraries and uncheck songs and videos that you don't want syncing to your devices. We do this frequently for songs or videos that we don't need any longer while on the go.
Compatibility: iPhone, iPod touch, and iPad.
