Getting in the habit is the hardest part, believe me. But, as you go along, you'll find it gets easier to remember to RC, and you start relying less on aids, like post-it notes or writing on your hands. Getting in the habit of RCing without these aids is also a great way to train your prospective memory, which can also be used in becoming lucid. I use three RC's: memory, nose-pinch, and finger-through-palm. The last two are relatively self-explaining, but the first is one of the most surefire ones, in my opinion. Basically, if you're having trouble remembering what you were doing five minutes or so ago, there is an excellent chance that you're dreaming.

Awareness is also key. As your dream journal grows and you start identifying dream signs (which don't have to be specific recurring elements, I may add), you'll be able to fine-tune when and where you reality check, and for what reasons. All of this will definitely help you to become lucid.

A closing note on the matter: do NOT do RC's absent-mindedly. ALWAYS assume that you're in a dream when you're actually doing them. If you glaze right over them and don't really pay attention/assume you aren't dreaming, then you will be quite unlikely to notice them when you actually ARE dreaming.