While I have never been able to maintain any controll over anythign in my dreams yet, there have been many times where I have realised I was dreaming and took on a role as a sort of spectator. In a few of my dreams which i “spectated(Can’t treally think of how to describe it, maybe some of you can relate ot this?)” there have been times when I would try to hit or punch someone or something but just before contact was made some kind of force would sort of stop my fist and sort of push is sideways and then let it go past the person or object. The person or object would remain stationary as I would try several more times to hit them or it but never succeed and end up feeling extremely frustrated, anyone know why that is?
Hey Hex Oxide, welcome to the forum.
Your problem exists because you believe it does. Convince yourself in the LD that you can really control anything that happens. It is advised though to start small, like pushing your hand(s) through solid objects etc. Try this in your next LD, good luck! 
Hi Hex Oxide! Welcome to LD4all!
Sometimes I’ve some problems while trying to control my body during LD’s. For instance, I was once practising kung-fu with a master , my punches were rather quick, but my arms were very slow when I wanted to take them away.
I don’t think it’s very important. Sometimes you can do something in LD’s and you cannot do it again in another LD, and vice versa. So, just try again! 
Ive had a similar problem I can only fly in lucid dreams. I have had two and in both all I have done is flown. Dont get me wrong. Flying has been a blast, but everything else seems much more difficult. I also have a problem remembering what I want to do, during the day I have so many ideas but in dreams all I can think of is flying. I dunno why.
But I wasn’t actually trying to do anything, it was like I was watchign myself from inside of me o.O I don’t know why I tried to hit the people and things, I wasn’t trying to make myself do anything but whenever contact should have been made it was prevented.