Your first stop should probably be a sexual health doctor or sex therapist, who will likely encourage you to explore your own sexual response. "Have you tried a vibrator?" asks sexual medicine specialist Andrew Goldstein, MD, an associate professor at George Washington University. "I tell women they need to masturbate!" says Hilda Hutcherson, MD, an ob-gyn professor at Columbia University.
Do you prefer a light touch or a firmer one? Do you want your clitoris to be stimulated or your vagina to be penetrated, or do you need both at the same time? Despite the impression you may have gotten from romance novels, many women don't have orgasms from vaginal penetration alone. A 2003 German study found that 70% need direct clitoral stimulation in order to achieve orgasm.
While most cases of anorgasmia (the medical term for not being able to have an orgasm) are psychologically or culturally based, there can be medical reasons for the problem, too, so it's important to consult a doctor, especially if you used to have orgasms. Anorgasmia can happen for all the same reasons as low libido: reduced blood flow to the genitals due to disease or medication, hormone imbalances, or the use of medications that dull sexual response.