They key to anything related to lucid dreaming is such: practice + confidence + a little bit of imagination thrown in. I used to be able to do some cool things in my (non-lucid) dreams when I was younger, but I, too, lost that ability for some reason.

I would recommend that you decide specifically what you want to do in your dream the next time you become lucid. Then, just do it (thank you, Nike). Don't spend your time thinking, "I hope this works," or "What if this doesn't work?" It will if you don't think about it too much. And the more you practice at it, the better you'll become. Just keep at it!