Most of my dreams are low level like you describe. I can control my actions, maybe fly or walk through walls, but haven't been able to get much control over dream characters or the environment and have never felt the full lucidity that lowercase describes.

In a paper by Laberge, he said something to the effect that there are two dream contexts - a lucid dream context and a subconscious dream context. Both are fighting for control of the dream and if you get distracted by the subconsious dream context (environment and other dream characters) you can lose or lower lucidity as the dream progresses. This often happens to me. So, my plan for my next LD is to try to ignore the dream characters and find my own space without distractions to experiment with my senses and see if I can achieve and maintain a good level of lucidity.

Would appreciate any other ideas on how to achieve higher levels of lucidity and control.