You can, Steph!
A lot say it is not that the dream was initially vivid, but it depends on how aware you are.
Sageous says that self awareness increases your experience in a LD, and it definetly helps in dream control. Im not sure if he meant increases the vividness too, but more awareness will make the dream more realistic, and more self awareness means we are more aware that we are dreaming. I think, with self awareness, a long WBTB, and Sivason's very effective stabilization techs, you can get a very realistic LD, but I'm not sure.
I found that the long WBTB does the trick, increasing awareness in NLDs thus it becomes more realistic. Then you become lucid, and BAM!! Very realistic LD!
I'm just guessing. I'll start a thread about it.