Check out Mark Kistler on YouTube. I'm not sure where you are from but he was Commander Mark on 1980's TV in America (I'm from UK so don't know him from there just from the internet!), teaching kids how to draw. He has a really great approach to teaching how to draw in 3D, and he is a really nice guy. He does a live video everyday but you can watch them any time (plus he has over 1000 videos on his YouTube channel). I didn't think I could draw either!