Lucidity comes from the higher cognitive functions of your brain. Without waking them up during R.E.M.  it is impossible to achieve high level of lucidity. You can try practicing awareness during the day but it is unlikely to help you during sleep. Assuming such practice indeed heightens your awareness to a higher level, it's still not going to help you because when their corresponding regions are suppressed you don't get to use all that extra awareness anyway.

Dream vividness depends on several factors, to name a few:

1. The perceived vividness after you wake up. It is normal for us to forget our dreams. Even when we do remember them they no longer feel as real. This is a safety mechanism and you'd better keep it that way. If dream memories don't fade they can become very problematic.

2. The stage of sleep.
3. Your brain condition and physical health.
4. The cooperativeness of your subconscious.

During lucid dreaming there are techniques to make the dream more vivid, but this doesn't seem to be your question.