Lucid dreaming is simply becoming aware that you are dreaming without waking up from your dreams. With enough practice and control you can turn your sleep time into a form of active awake time that has a virtually endless amount of possibilities.
Develop the ability to recall your dreams by focusing on remembering them just before you go to sleep. Without enhancing your dream recall you won't be able to remember if you've had a lucid dream or not. Clear your mind of all other thoughts, and concentrate on not forgetting the details of your mental adventures. Mentally preparing yourself to remember your dreams will help trigger your brain when it's time to put them down on record.
Keep a dream journal of all the details you can derive from memory the moment you wake up. It helps to leave your journal next to your bed, so you can reach for it as soon as you open your eyes. Write down as many key details as you can without allowing your mind enough time to erase the dreams. Recalling your dreams in reverse is sometimes easier than trying to start from the beginning.
Be aware of items, images or themes in your dreams that can be used as signs to cue your brain into inducing a lucid dream. More often than not these signs will be something seemingly impossible, such as the ability to fly, a purple sky or a blue dog. However they can also be something ordinary like a broken light switch, losing the ability to talk or finding yourself suddenly naked. Training your brain to recognize these signs will help you on your quest to inducing a lucid dream.
Go through your journal after a few weeks and see if you recognize any recurring items, images or themes. These can be used as personal dream signs that will signal your brain that you are dreaming, and allow you to induce a lucid dream. Make note of these signs and be on the lookout for them in your next dreams.
Perform reality checks on yourself throughout the day by stopping to ask yourself if something actually happened. This may seem a little weird at first, but it will help train your mind to ask these types of questions when you are asleep. Thereby increasing your chances of recognizing dream signs.
Maintain your lucid dream state once you've recognized that you're dreaming by spinning around in a circle or concentrating on your hands. Most often you will find your dreams slipping away as soon as you realize you are dreaming, so it is important to relax and focus on these seemingly silly techniques in order to allow your brain to let you stay in your lucid dream state. You can also try telling yourself out loud not to wake up, or experiment with your own technique.
Exert control of your dreams once you have maintained and relaxed your lucid state. Your dreams are now your own personal playground, with your imagination being the only limitation. You can literally do whatever you want.