I am able to become lucid… I did it last night, but I couldn’t do anything I wanted no matter how hard I imagine I have powers of my mind, I can’t do anything. It angers me because I tried to summon my bf, but he didn’t come… then I tried opening a door but to no avail. I have tried to fly on a broomstick but it doesn’t work. I have tried everything, could someone please help me? 
Practice makes perfect!!
Most of the time, I usually manipulate characters to help me.
Say I’m trying to summon a person, I tell a DC already in the dream to go fetch that person for me and he or she usually does.
Same would go for the broomstick. Ask the DC that’s already there to enchant it and make it fly. 
Hope that tip helps a bit.
hmm… sometimes when you want to do things in your dream and you are just a tiny bit skeptical that it could work… that´s enough for it to not work. so be very very confident in all your decisions in your dream
another tip that could solve your problem… is that whenever you want someone to appear, you usually just don´t make him appear out of nowhere… call him as if you were looking for him, shout his name! and he will probably come to you asking whats up…
another way is imagining that person is behind you… visualize it… or even better just say it. then you turn around and chances are he´ll be there.
and the toy master is right… using other DCs works great. Good luck!!
Thanks
As Toy Master said…
Practice makes perfect.
It’s a skill you will acquire with time.
transL gave some good ideas about how to summon things.
The main thing to keep in mind is to that you do control it even if you “fail” to. Just relax, know and realize your abilities and you will surely be able to do anything at all.
It usually takes more than one dream to start flying around and making your friends come.
You’ll soon be able to concentrate and bring your friend or fly some and not long afterwards you’ll find yourself creating whole worlds, flying and summoning people just as easy as it is to clap your hands together.
Don’t worry about it, just enjoy yourself