One of the best ways to become a better lover is to talk to your partner and find out what they like.
Before you have sex, agree that you want to find out more about what your partner likes. If you've normally made love in silence, they may feel too inhibited to respond if they're not forewarned.
Next time you're caressing your partner, ask for feedback. Think about what you're doing and what information you need. For example: "Would you prefer me to touch harder or softer?" "Do you prefer long or short strokes?"
Agree on a scaling system, so you can ask how much something turns them on. For example, zero can equal nice and ten can equal orgasm.
If you or your partner finds it difficult to describe what you'd like, try the hand-over-hand technique. When you want to show them what to do, put their hand over yours or put your hand on top of theirs and guide them.