1. Open iTunes.
2. Select the song that you want to be your ringtone.
3. Listen to the sound and mark down the start & end points
4. Right-click the song and select “Get Info”
5. Go to the “Options” tab and fill in the “Start Time” & End Time”
6. Click “OK”
7. Right-click the song again and select “Convert Selection to AAC”. It will create a duplicate version of the song.
8. Right-click the duplicated version and select “Delete”. Select “Keep Files” when prompted.
9. Go to the folder that contains the duplicated song file. Usually in the user folder under “Music > iTunes > iTunes Media > Music” and under the singer’s name. It will have an extension of m4a.
10. Rename it to m4r.
11. Double click the m4r file and it will be loaded into iTunes.
12. Connect your iPhone and sync your ringtones.