Before attempting to become lucid, I suggest to practice dream recall, until you reach the point of at least one recalled dream per night. This has one very obvious reason. You want to be able to remember being lucid in your dream.
There are many techniques that help inducing lucidity. Some of them can be combined to increase the likelihood. Sleep interruption
One of the easier techniques is sleep interruption. This means, waking yourself in the middle of your normal sleep period and then falling back asleep a short time later (10 to 60 minutes). I recommend you to use of a relatively quiet alarm clock which can bring you to consciousness slowly and naturally until you fully wake up. Then you can do some 'resting activity' such as reading (you may find it helpful to read some literature about lucid dreaming), subsequently falling asleep again. This period afterwards is usually mostly REM sleep, thus full of dreaming.
Drinking technique
This is more biorhythm based technique, based on drinking loads of fluid (water or tea) before bed, to induce waking you up. I suggest to drink water or fruit tea, as black tea contains caffeine, which may affect your ability to sleep. However, you may want to try to have a cup of tea or coffee just before bed as you will probably fall asleep before it takes effect. The caffeine stimulates the mind, which could help you to induce lucidity. I find this method somewhat uncomfortable. However, you should try to experiment with different methods as what doesn't suit one may fit to another.
Troubles falling asleep?
If you have difficulty falling asleep, it is not wise to drink too much liquid longer than one hour before your bed time. You would probably find yourself needing to visit the bathroom just when you are about to fall asleep. As mentioned above, avoid drinks containing caffeine for at least six hours before sleep. Please, keep in mind that there is no universal formula to lucid dreaming and different things work for different people. Exercising during the day usually helps falling asleep and the sleep continuity.
