My advice to anyone who is nervous about starting to use CAD: find some a set of videos which can explain how you use it, step by step. I was a bit daunted by the learning curve, but I found a cheap CAD program with a good set of instructional videos available: TurboCAD (the 2D version):
I have now moved onto Rhinoceros. Rhino has a very different way of getting things drawn and it took me a while to get used to it, especially because I’m now working in 3D rather than 2D. To learn Rhino I used a similar approach to learning TurboCAD: I completed the accompanying tutorials, complete with exercises, to learn one piece of functionality at a time.
I found out about Rhinoceros when I saw it being used by the designer of Solar House 2.0, a modular CNC-cut shade house in Spain. I was intrigued by his use of a plug-in for Rhino called Grasshopper, which enabled him to use variables for various lengths and angles; by just changing these values, the design would redraw itself automatically. Something I might look at later.