It is axiomatic that people in a videoconference will suffer variable video willingly, but have very little patience for poor sound quality. This is a very difficult issue to deal with electronically. Fortunately it is relatively easy to deal with mechanically. This can be accomplished by using carpeting, acoustical ceiling tile, and drapes.
Ambient noise is another major problem.
Do a tape recording of the background noise in the room you plan to use. Take the recorder into a really quiet place, turn up the volume and play it back. Whatever noises you hear on that tape will be going, amplified, to the other end of your videoconferences as well. Our biggest ambient noise problem here is noisy air handlers. We will try to address this by wrapping the ducts in fiberglass batting.