The manually managing feature lets you choose just the music, video, and podcasts you want to have on iPhone.

Set up iPhone for manually managing content:

Connect iPhone to your computer. In iTunes, select iPhone in the sidebar. Click the Summary tab and select “Manually manage music and videos.”

Click Apply.

Add items to iPhone:

Drag a song, video, podcast, or playlist in your iTunes library to iPhone (in the sidebar). Shift-click or Command-click (Mac) or Control-click (Windows) to select multiple items to add at the same time.

iTunes syncs the content immediately. If you deselect “Manually manage music and videos,” the content you added manually is removed from iPhone the next time iTunes syncs content.

Remove items from iPhone:
With iPhone connected to your computer, select the iPhone icon in the iTunes sidebar. Click the disclosure triangle to the left of the icon to show the contents. Select a content area, such as Music or Movies, then select the items you want to delete and press the Delete key on the keyboard.

Removing an item from iPhone doesn’t delete it from your iTunes library.