What is the best way to spice up your relationship and bring the heat, passion, and intimacy to a new level?

My boyfriend and I have been dating for 8 months now. He knows practically everything there is to know about me, and I him. We have become so comfortable with each other, no subject is awkward or uncomfortable for us to talk about. However, as much as we love each other, I can tell that he would like things to be as spicy and heated as they once were at the beginning of our relationship. Do you have any helpful tips to reheat the flame between us and make my man go crazy for me even more?