Sounds to me that you lack conviction and perhaps even knowledge of the fact:

Your Dreamworld is YOUR domain. In YOUR imagination. You have full control of everything because in there you are a GOD. The only reason that you may SEEM to have little controll over your Dream is the false belief that somehow you wouldn't be able to control it. Probably based on countless non-lucid dream experiences where you were helpless.
If you have problems with anything in a dream, for instance flying, you get back on the ground, nod your head in shame of the miserable first attempt due to false incertainty and then you Shoot up into the sky like superman.

As hard as it may seem; It'sw a question of certainty. Be certain you can do it. If you feel you can't do something shudder it off and just do it like you know you can. A God with lowself eshteem is not a God at all.