Lately I have been thinking of a particular goal, and focusing on achieving it once I go lucid. Having some kind of goal and also constantly reminding myself I am lucid and aware are some ways that work. A little meticulous constantly reminding myself I am aware and lucid though... so I have been seeking out meditation as my goal in dreams lately. I've done the rubbing hands thing too, or looking at my hands every so often.

And as Mancon said, using all your senses is a great way to maintain lucidity!