To elaborate a bit on the cliff notes version AdviceDoc just gave - we keep dream journals, where we write down all the dreams we can remember when we wake up. As you do this it helps you to be able to remember more, and in better detail. Thinking (and writing) about dreams helps to focus your attention on them. After a while, looking through your journals you notice certain recurring elements that show up a lot in your dreams - some of them also show up in waking life, like your bedroom maybe or people you know. Some show up only in your dreams. Make a list of these dream signs and whenever you notice one of them do what's called a reality check. This is to determine if you're awake or dreaming - because the problem is that when you're dreaming you believe you're awake, even if you're floating through the air and a giant laughing Budha is juggling houses in front of you.

If you establish a habit pattern in waking life of always doing a reality check (we just call them RC's) whenever you see one of your dream signs or when things feel a little weird, then sometimes, even when you could swear you're fully awake, you discover you're actually dreaming. Let's say for instance one of your dream signs is a dog you used to own who's no longer living, but sometimes shows up in your dreams. This happens to me a lot - in fact I see a lot of dogs period in my dreams, so dogs are one of my DS's. When I see one (if I think to) I'll do an RC. The best one is the nosepinch - pinch your nose shut and try to breathe. If you can, then you're dreaming (there's no way to stop yourself breathing in your sleep, so it almost always works). The second best one is to press your finger into the palm of your other hand - just press gently for a moment or two. In dreams it will usually go through after a moment of resistance. It's weird - nobody knows why it works, but it does. It doesn't hurt or bleed or anything - it's more like sticking your finger through some bologna or something, and sometimes you can kind of feel bones in there, but there's no pain. When you try an RC and it fails, then you know you're dreaming, and you can fly around or do whatever you want - it's an amazing feeling.

If you want to learn all about lucidity, the best reference (besides Dreamviews of course!) is the book Exploring the World of Lucid Dreaming by Stephen LaBerge. But of course there are also great tutorials here in the DV Academy (click on Forum at the top to find it) and it always helps to read threads or read people's dream journals.