I am no expert but the one rule that changed my cornering:
"Weight the outside peg"
You're going into a right hand turn, slight berm:
- elbows up
- shift your butt up the bike almost on the tank
- as you lean the bike to the right, shift your butt so the left edge of the seat is wedged in to the crack of your butt, so the bike is leaning but your body is vertical
- poke your right leg out and forward
- literally try and stand up on the bike using ONLY your left leg, but don't actually stand, therefore placing a great deal of pressure on the left peg
This shifts the center of gravity to the left, away from the lean, preventing you from sliding out.
Once I got the hang of it, I found the bike was literally sticking to the corner. Problem is, it's bloody hard work so you (I!) need to be lean and strong to do it consistently.
I also use this when going through sweeping turns that are quite bumpy but I lift my butt slightly off the seat so my leg absorbs the bumps. Again, quite tiring for an old fella like me.