I got this idea from a friend and have never tried it but

Dream normally for a while and when you wake up in the morning make notes about your dream in a dream diary
After a while you will start to notice something that you see regularly
Say for example you see clocks in your dreams
When you see a clock in your waking life do something you would not normally do like look at your watch or do a star jump
Now here's the big bit keep doing that
So when you see the object in your dream you do what ever you chose to do in your waking life
when you do this in theory you should find out that it is a dream and start controlling it
but keep practicing because it will not work over night
Happy Lucid dreaming