First thing is to realize that it's a dream
before you wake up. Really hard to do at first, but gets easier.
From that point on, (literally) use your imagination. It's your subconscious mind creating a situation and environment--your imagination can "tweak" it in any possible way (and since it isn't reality, all the impossible ways, too).
I've kayaked away from charging T-Rexes in upstate Sasketchewan, visited Pluto, made myself impervious to bullets, flown at will, even reversed a "falling dream" to where I was rushing upward.
It's a lot of fun if you want it to be.
Wierdest thing for me, though, is that I cannot read books. I've had lucid dreams where I've got a huge book sitting right in front of me, but I can't read a single letter on the pages.
Signs and everything else come out fine, but not books.