I don't feel fully in control of my LD's

[N1GHTMARE]

I'll try to keep this short.. I recently experienced my first lucid dream on accident.. it happened when I realized I couldn't run, and I fell down laughing and shouted in my dream, "I'm dreaming!" .. I don't remember much after that, so I assume that I woke up briefly. I'm not exactly sure how I became aware that I was dreaming for my second lucid dream, but once I was, I was able to run, fly, and make things appear when I wanted them. *** My third and most recent lucid dream made me realize how unpracticed I am in controlling the events within my dreams. Although I was aware that I was asleep, I had difficulty in making things go my way. I told myself that I wanted a specific object to appear in a specific place, but it did not happen. (I don't know if this is even something that I should be able to do: can anybody provide insight?) In the two most recent dreams, I felt like my sub-conscious mind still controlled about half of my dream, and like I was only consciously in control of the other half. I would like to know if more control will come with more practice, or if there is something I should do to make my lucid dreams more "obedient" to my wishes. Also, in the last two dreams, I had to escape capture/death. I knew that I had the choice to change the dreams, but I had fun fighting my pursuers (both were Harry Potter related :]). ***There was another dream that I remember being lucid in, but I think I woke myself up. I remember that it was another dream involving a life-or death situation, and it was too stressful and frightening to remain in. Are my violent "half-lucid" dreams something to worry about?