First, download AUDACITY, the open-source audio editor.
In the latest version is a new tool called Vocal Remover that you can use to at least, as implied, the vocal track from a song, to make its easier to fret guitar. It works on most modern recorded music (that is, recorded with multiple tracks).
- Import the song into Audacity.
- Go to Edit>Select All.
- Go to Effect>Vocal Remover (for center-panned vocals).
- Click OK, let the effect render, and play back your file. If you're satisfied, export it. If not, undo and fiddle with the band range to be removed and try, try again.
This is another trick that sometimes works for removing all other instruments besides guitar.
- Import .mp3 into Audacity (The song must be stereo)
- Split the stereo track
- Highlight the 2nd track.
- Go to "Effects" and click "Invert"
- Duplicate/copy the 2nd track and paste it (You should have 3 now)
- Set all the tracks to "mono"
- Track 1 will now be your guitar
- Tracks 2 and 3 will be the rhythm
The song should still be the same (Except of course in mono)
There are no differences in sound, but the guitar will be slightly audible during the song (especially during solos)
To test and see what the song will sound like, just hit "Mute" on the first track.