Keeper, for me it usually just takes practice; no matter how many times I visualize what I want to do, I've got to try several times in a lucid before I'm actually able to do it. (I'm not a good "visualizer", however, so maybe you are better.) You did pretty good; you did manage to phase yourself, so you'll be able to do it again.

And for spinning--you just do it, it's hard to describe. I haven't really tried that many times; I don't usually remember to do it, but sometimes it works and sometimes not. When it works, you feel like you are spinning around really fast, faster than you could IRL. When it doesn't work, it just doesn't. I don't know how else to explain it.

I know that's not helpful advice, but I just wanted to let you know that these things don't come easily to me either. Just keep practicing--if there's something you really want to do, eventually you will be able to do it.

It's hard to stay in the dream when you get to that point where you're about to wake up. Focus on detail, if you can see anything at all; if everything goes black, try to visualize the last thing that you saw, and it may come back.