I would like to somehow pick your brain about environments. I can't seem to cull them from my imagination. Should I just draw landscapes for awhile and see what happens?
It never hurts to practice and study reference for environments, but it's also important to be constantly observing; how the door to a restaurant bathroom looks, how the lower branches on many trees are horizontal while the upper branches are more vertical etc...etc. Always have a horizon line, even when drawing cartoony backgrounds. That way you will always know if you are viewing something from above or below. However, I find some artists tend to struggle more with scale than perspective; for instance having doorways that clear an average persons head by only a couple of inches or buildings that would have the square footage of someones living room. So, even when drawing an environment without anybody in it, it's always good to rough in a figure just for scale.
Just remember: it's not necessarily what's correct, but what looks good. Lecture over.