Those sound like more or less common problems. It seems like your two main ones are dream stabilization and maintaining awareness. These posts may already be enough to solve your problems:
[Dream Control Training Course)
[Prolonging Lucid Dreams)
[Techniques for Longer Lucid Dreams [by Robert Waggoner])
What can prevent you from losing lucidity is to repeat (either say it out loud or in your head) “I’m lucid” or “I’m dreaming” etc. If you start to doubt whether you are in a dream or not do one or more RC’s to verify it.