The first commandment is to pay attention!
Pay attention to how they react when you do something, or say something, or even think something inside yourself.
Touch them and pay attention - how are they responding? Do they like it? Look carefully at their body movements, facial expressions, listen carefully to their voice.
Try different things. The things that work and make them happier, you keep. The things they don't like, you don't do them and discard them.
Over time, you'll get to know your partner really well and you can use what you know to excite them more, or to hold them at a certain point, slow them down, speed them up.
Just pay absolute attention to the cause-and-effect of how what you do affects your partner and learn. Eventually, this turns into a much more natural flow of interaction, but it all starts with paying really good attention to your partner.