I'm not sure if this is already a method, but all You have to do is before you go to sleep, and right when you wake up, Count how many fingers you have on your left, then right hand. (more or less than 5 [obvoiusly] means your dreaming). Try sticking your right index finger through your left palm, then your left index finger through your right palm. Plug your nose and try to breathe through it. and Your done.

If it's not enough for you then read a paragram from a book or something.

This method worked for me just fine..I started last week and I've had my first 2 lucid dreams this week.

(i'm pretty sure this already is a method, but just doing those 3 simple reality checks works perfectly)