Know that you deserve it. Every woman deserves intense, empowering pleasure. Allow yourself to truly believe that and it will be easier to ask for what you want.
Journal your deepest, darkest desires. It could be the problem is that you're not even sure what you're looking for in the bedroom. Try writing your wants and needs in a journal first. Don't censor yourself, set a timer and write for 15 minutes and see what flows. Once you have a clear vision of what you want, it's easier to ask for it.
Ask your partner what they want first. Chances are after they answer they'll ask you. Be open to giving them what they want.
Stay positive. Say what you want, don't complain about what you're not getting. Start with a compliment about something they are already doing right & add in something new you'd like them to try. "I love the way you kiss my neck, it would be amazing if when you're doing that you also...(fill in the erotic blank!)"
Be specific. Your partner is not a mind reader. If you never ask, they'll never know.
Practice. Stand up for what you want in other areas of your life. You'll find that being your own advocate is empowering and can help you find your voice.
Make a "sex talk" appointment. We know, setting time on your calendar seems pretty unromantic. But setting an appointment will show yourself and your partner that a satisfying sex life is a priority. If it's important enough to put your haircut on your calendar, it's important enough to put your love life on your calendar.
Plan a date night. Sometimes a night away from the stress of work and home is all you need to re-ignite a spark.
Whisper sweet (erotic) nothings to them. Take the pressure off your partner by whispering exactly what you want from them when you're outside of the bedroom. Then you can just sit back, relax and see if they act on it later.
Show your partner. Sometimes you don't even need words. Use your hands to guide your partner's hands exactly where you want them.