1. Know thyself
What's good for the greeks is good for orgasms. Knowing what turns on your mind and your body is a good place to start, and prioritizing your own pleasure—in life, not just in bed—helps you open up to the idea of having more. Spend some time masturbating and getting to know what feels good to you so you can communicate it to your partner.
2. Get comfortable
Being hot, cold, or constantly worried that your six year old is going bust into the room is not conducive to enjoying the moment. Similarly, try to get comfortable in your own gorgeous skin. Worrying about how your thighs look in the light has never helped anybody come once, let alone twice.
3. Relax and take your time
Going for a multiple orgasm should not feel like trying to ace your SATs. There's no deadline, there's no pressure and you can do it as many times as you want. And if you're with your partner, let this be all about you. You can reciprocate on another night.
4. Practice makes perfect
Forget diamonds: Kegels are a girl's best friend. This simple exercise makes orgasms more intense and makes it easier to have multiples, no gym required. In fact, you can entertain yourself by doing it in traffic or your department's Monday morning meeting.
Whether you're with a partner or on your own, try teasing. When you feel yourself building toward orgasm, shift your touch (or direct your partner to shift his; his tongue is particularly good for this) to a place that's slightly less sensitive, then move back. Even in a series, each orgasm has its own build-up, and learning to navigate increasing and decreasing sensation will help you get to higher and higher places without going over the edge. Alternately stimulating the clitoris and the G-spot can help, too, since they produce pleasurable, but different, sensations.
6. Speak up