Communication! What do you like? What does your partner like? It might sound counter intuitive to talk about what you'd like to do, but just talking about it is a massive turn on for a lot of people. Massages, some candlelight, relaxing music, taking a shower or a bath together...there are tons of things you can do. Just use you imagination. You guys could strip for each other, watch each other masturbate a bit, confess your fantasies (take that one slowly though, and make sure both you and your partner have an open mind)...just take your time and explore each others bodies AND minds. Foreplay is also psychological and emotional, not just physical.