Don't Go Too Fast
If it feels as though foreplay has gone on long enough, it hasn't. Spend as much time as you think is humanly possible on foreplay, then keep it up for another twenty minutes. That might be enough.
Don't Caress In Straight Lines
Tactile sensations are better when a touch is unexpected. A caress in a straight line is predictable and not as powerful. Move your hands in erratic patterns as you touch her.
Don't Grab Her Head
Most women do not like having their face pushed into a pillow, hair pulled like a rope, or ears gripped while their giving you head. Go figure, they're funny that way.
Don't Stop For A Break
A lot of men like a little break in tempo and pace while they're making love. Most women prefer a steady approach. If you stop just before she comes there is a good chance she won't come at all. Keep it up, whatever you're doing (licking, stroking, fucking) and don't change the tempo.