The key to good pking is knowing when EXACTLY to eat, when to switch weps. I've been 'combo breaking' for half a year, it's when you switch to 2 special weapons after you've hit with your main weapon. Example --> Rune knives --> Dark bow NORMAL shot --> Gmaul spec. If you time this correctly your opponent has like no chance in the fight.
To make things short --> know that when you've eaten you won't hit your opponent always as fast as you want, try getting on a private server and use the combo i told you about ;)