Reply to Soundproofing your setup's space

Does anyone have any experience or insight on soundproofing a room/place for music production? Any info is appreciated.

I'll start with a few basic tips I learned from experience:

1. Cover open space like door frames, window frames, etc with tape (weather proof) or some object (a towel over the open space on the bottom of a door).
2. If you have open hallways in your place, install a doorframe and door. This wasn't too expensive and worked pretty well.