Alright, so this is my situation: I've had about 27 lucid dreams, and about 80-90% of them have ended almost instantly. However, I feel confident that I've already gotten the part about staying calm. This morning I had a lucid dream that led to a theory about my problem.
For quite a while now, I've been greatly interested in possessing someone in a dream. I managed it just once before, and it was so cool that I had to do it again. Anyway, most all of my lucid dreams since Christmas have been very short. They also have all began with me trying to possess someone.
Last night I forgot about possessing someone for a while in my dream, and I ended up flying around a town a little. I then went over to a bathroom and remembered about possession as someone came out. I followed them for a while, but then they ran away from me. At this point I decided to summon someone to possess. I closed my eyes and shouted, "Summon (and then the person's name, which I won't reveal)." I failed to summon the person, but just seconds after trying the dream ended.
So this is what I'm thinking: can trying to possess or summon someone end my lucid dreams prematurely? Do I need to spend extended periods of time stabilizing before even trying? Help and advice would be much appreciated!