Re: Bareknuckle fight
If the guy is as crude a fighter as you are describing, he may try to bullrush you. Sidestep him and pot shot him as he goes past you by either pivoting on your lead foot and throwing a left or pivoting on your back foot and smacking him with a right if you fight in a conventional stance or the opposite if a southpaw.
Another thing I liked to do was toss a few jabs to see how my opponent reacted. A few times they would follow my jab with one of their own. If he does this, toss out a few jabs then feint one and when he tosses his out, duck under and shoot a hard right to the solar plexus. I've dropped a couple guys with this and they don't get up fast. It's pretty much fight over if you knock the wind out of an opponent.
Liver shots with hooks are great punches and the advice about avoiding the forehead and mouth is right on, especially bareknuckled. If you cut your hands on his teeth there is a very good chance you will get a pretty nasty infection in your hands that will take a good bit of time and cost to get rid of.