Good thread. My thing is that I like having my wife lie on her stomach, so I can give her a good back massage. The massage progesses to a point where I spread her legs by pushing her knees apart (about as far as I can w/o making it uncomfortable) so she feels very vulnerable. I then spend a lot of time lightly stroking from her knee along the inside of her leg up to - but not directly touching - her kittie
I'll then use my thumbs to spread her lips far apart, again while not actually touching her lips and while she is still wearing her panties. This get her relaxed and then very worked up.