Well you can think of reality checking in this way.

You didn't mention of you're keeping a dream journal or not. But if you don't, time to get on with it! Every time you remember your dreams, write them down.

Now over the course of your dreams, you can start to go through your recorded dreams and see if they have any kind of pattern, of any kind of specific thing it seems like you're experiencing regularly. For example, say that in almost all of your dreams, you sit in a car, everytime you get into a car in real life, you ask yourself if you're dreaming or not, and try to really mean it.

If your dream signs are hard to link to anything in your ordinary day to day life, then you could try and do reality checks regularly doing the day, but you have to remember to try and REALLY ask yourself if you're dreaming or not, but a bit skeptic and question your current sorroundings. Might sound dumb, but that's the way to do it, else it won't really get into your consciousness

You should also read these two tutorials:
http://www.dreamviews.com/community/...ad.php?t=65236 - Dream signs

http://www.dreamviews.com/community/...ad.php?t=75427 - Reality checks

And yes, I have had lucid dreams through random reality checks Where I look at my hands and figure out I'm dreaming.