for my chin i find a good skin stretch makes all the difference. i found that going WTG straight down with my thumb under my bottom lip pushing up and then doing the same WTG but putting my thumb and pointer on either side of my adams apple and just up a bit and pulling down on the skin. then i finish with XTG goin from the middle of teh chin and out. i find that if i set the razor flat on my skin first and then adjust my angle up at this point i get less nicks. there are many ways to do it, this is mine.

good luck
Wes