I pretty much self-taught myself to draw anime/manga-styled drawings as well as sculpts/3D modeling. I never had an art class that taught how to draw or sculpt anime. The only real thing I have learned from art classes were things you'd use in realistic drawings, such as shading and "draw what you see, not what you think you see"(which does NOT work for anime characters).
I guess the most useful thing school taught me about anime drawing, is that eyes should be around the center of the head, and about an eye's width apart.

However, I never got really good with technical stuff like proportions until I started using Google to look for reference photos of the human body.

Well, now people say my stuff looks pro, so I would say I've been successful without much help from classes, besides anatomy/proportions. I think the majority of my skills came from careful observation, enjoying it as a hobby, and perhaps natural talent?