Remain calm and proceed to amplifying the unusual sensations whatever they are. They indicate that you are entering that hybrid state of mind that is required for lucid dreaming. If there is no visual stimulus but sounds and/or vibrations are present, simply make them reach a peak and them act as though you are separating from your physical body.
Don't imagine movement, actually move. When you do this you will most likely move with your dream body. Bear in mind that dream body movement can be indistinguishable from physical body movement so don't assume that just because it feels like you simply got up that you ruined everything.
Look around for clues that you are in the dream world and not the real world (you might find inconsistencies in your "bedroom"). If vision is absent or you're partially blind (like you've got eye gunk), then a very useful trick is to rub your hands in front of your face. Pay attention to the tactile sensation, the warmth, the sound of rubbing and you will find that vision will follow splendorously. Expect to see, btw!!
Your surroundings magically lighting up should be enough proof that you have indeed entered the world of lucid dreaming. Good luck!
"Empty cognizance of one taste, suffused with knowing, is your unmistaken nature, the uncontrived original state. when not altering what is, allow it to be as it is, and the awakened state is right now spontaneously present."