sex advice!

Okay so I'm not too experience with the whole sex thing, but my bf and I have been going out and having sex for 3 months. He does most of the work in bed, mainly because my ass gets tired real quick especially when on top. ANYWAYS what can I do to be a better lover? Hes not much of a foreplay person he just throws me into bed haha. How can I spicy it up! Ladies I need to know the tricks you do!