Teasing is my favorite part. I really like to prolong the anticipation. So a good ebb and flow between denial and pleasure really gets me going.
A few things that I enjoy, in the verbal department, being told how good the person is going to make me feel, in graphic detail, then being reminded about how much I really want it, but will have to wait.
Physically, I love being able to feel wet warmth of lips and tongue on sensitive areas like the back of my neck, earlobes, inside of hips, inner thighs, inside of my arms. That, combined with "almost" touching or grazing very sensitive areas like labia or nipples, and then going back and forth between "almost enough" and "not enough" is really very arousing.
I'm getting close to ovulation, so my imagination is definitely on overdrive right now!
Great question, OP.