So far I’ve had a couple LD’s but as soon as I realize it I try to make something happen but everything just goes black and I slip back into normal dream. Any advice?
That happened to me kinda when I tried to make other characters behave how I wanted them to, they just took over and I lost the lucidness D:
Was yours to do with the other characters? Cause my first lucid dream in making things appear and changing myself went fine and in 3rd I just went along with what was there and made sure I kept lucid. And those 2 were my clearest, and (mostly) away from other characters.
Have you tried to focus on stabilizing the dream before you try to do anything else?
It might help to reaffirm to yourself a couple of times that you are Lucid Dreaming.
It could also be because you are putting too much focus on what you are doing. Maybe you could try to keep it in your mind that you are dreaming when you go to do something. In the times I have lost lucidity in that way, it seemed to be because I let what I was focusing on take my attention totally. I also wonder if lucid living might help. Although these are just my thoughts, I’ve not properly tried them yet. 
This would happen when I would change the dream completely so if i realized i was dreaming in a classroom I’d try to change the setting to something more fun and lose it. I suppose if i remember, I’ll try to establish myself more next time before doing anything.
Best thing to do is just pretend as though you’re still dreaming, just observe and don’t take part until you think you’re ready to be able to do anti-life things like powers. See what’s going on, do some reality checks, but keep your cool in check and just think only of the dream, not real life. and test all of your movement, just try not to jump the gun to fast.
Altheman made the point, the ‘trick’ to having a ‘longer’ lucid dream is to gently follow it along, kind of pretending that you are still dreaming, stretching the limits a little by the time and not rush in to anything instantly causing your mind to get all overexcited (overworked)- This you can trust, for I haven’t yet had a lucid dream in which I haven’t done the same mistake, and it was only until recently (If you can call 4 months recently) that I figured it out 
If you want to change location, you could either do the door thingy (open a door and expect the place to be on the other side) or if you really want to be able to just snap your fingers and have the entire world shaking, you can do the door thingy to a middle age village with wizards and stuff, and pretend to be one 
As you get more used to the dream environtment you will also learn how to keep it stable and still do the things you want however you want.
Alright that sounds reasonable thanks everyone. 