I'm just like you and have the same problem. I'm no expert but what I generally try to do is "shock" myself out of sleep. This usually starts with jumping (literally jumping) out of bed. Then I turn the lights on and pace around my room. DON'T sit down, I fell into that trap once and you go straight back to sleep. If you're still tired by this point (remember you still have to be a little tired or you wont get back to sleep) go to the kitchen and grab a tiny snack (like one cookie or a bite of an apple). Food will wake you up instantaneously as your body associates it with being awake. From what I've heard the more ritualistic you can make getting up the better your body will get at handling it and the easier it will become to lucid dream on demand.