Stay on top of your max health, I have yet to get my average skill level above 40 because I constantly die from silly mistakes.
The biggest culprit is falling to my death because I feel safe in my zone and I forget to eat or casually run off a roof and die, the death penalty is steep at 80+ when it takes a hour to gain 1 level but it also teaches you not to make the same silly mistakes again, however some of us have given up achieving max skill levels since it can be console commanded and no achievement's to show for it