Have you completed the tutorials? That is a good starting point. But a knowledgable mentor will obviously teach you much more in a shorter period of time.
I have done several of the tutorials. Many of the tutorials are not very clear and I get hung up. This is very frustrating when you are trying to learn a small step. The video tutorials on line are not of high video quality. Fuzzy and grainy. It is very difficult to follow what is going on. And, When there is no sound it makes it every worse. I am looking for someone in my area that is using Rhino. Someone that I could spend a few hours with so that I can get going much faster.