Johan - Yeah, traditional paint is pretty scary. No undo button, haha. I got acclimated to watercolor pretty easily, but oil has been troublesome. It’s very complex, if you really want to get into it. It does seem that most places teach drawing for a while before painting, though, so I suppose you’re on the recommended track. And doing quite well, I’ll say! I’m loving the drawings you’re putting up these days. As for the paper, it depends. If it’s thick stock, there’s no trouble. If you’re using thinner paper, though, it tends to curl when it gets enough moisture in it. I had some curling trouble when I did a watercolor on charcoal paper. However, I’ve been oil painting on watercolor paper recently and haven’t had any issues. It’s a lot cheaper than buying a bunch of panels, and I like the surface better anyway.
I decided to just try painting with the paint right out of the tube, which is the way a friend of mine likes to paint. It turned out very well, I might say. Smooth surface + medium-free paint is a winner with me. 
As an example of such methods, here is a two-step still life I did.
Did a brown wash with turp to thin out the paint and make it dry quickly. Then I sketched everything in with turp and ultramarine blue.

A day or two later, I painted (mostly) with no oil. Just paint. It was actually FUN! 
