You have to be willing to eat a few deaths, but this is by FAR the quickest way.

Stack up as much +hp equipment as possible.
Go to Deormdel's shrine and pray until he appears.
Once he does, "dirt Deormdel".
He will slay the shit out of you, but he's so high level, you'll get at least 3 improvements in parry, 4 in shield block, and 2 in dodge. Not to mention the weapon improvements. And dirt.
Deormdel will then be mad, so it's Scarabaeus' turn... so on, and so on, until all skills are improved.

Good luck!