If you are of a mind to put your lips to her vulva, try some suction. Start by gently sucking her inner labia, then move to her clitoris. Don’t try to suck on just the clitoris, rather pull the clitoris and surrounding area into your mouth. Vary the suction – try both slow changes and rapid changes in suction.
Use your hands to move any hair away (it will prevent you getting a good seal) and to move her outer labia aside to gain better access. A pillow under her rear (with a towel on the pillow) will make it easier and more comfortable for you.