I had a lucid the other night:
Im in my front yard. I decide it is my dream and i can just make myself float up, however nothing happens. I try jumping, but still nothing. After i try jumping into the air several times, i decide i need to make a better effort. I run full speed and jump forwards with my arms extended hoping to fly, but instead I just bellyflop on the pavement and wake up shortly afterword. This is not the first time i havent been able to fly while lucid: gravity always seems to much for me to conquer. Any suggestions on what i could try?