First of all i found this information on an AP forum, but can't find the link anymore. Basically there it explained a technique to get lucid.

What you do for a few weeks is start doing reality checks whenever you need to go to the toilet, for a leak. Try to do this as often as possible so that it can eventually cross over into your dreams. After a few weeks you can try the technique. Before going to bed drink alot of water, this is so that your bladder fills up once you are asleep. Hopefully the urge to go to the toilet is enough to make you need to go in a dream. If this happens that RC may trigger you to become lucid.

This isn't the best methods i have seen, as it can lead to having to get up to releave yourself ect. But it is a very direct method to induce an ld if done right.