Everything I do is a constant learning experience. I started retouching using blur but stumbled upon Model Mayhem’s retouching forums, realised how bad this was and got a vague idea of dodge and burn and non-destructive retouching tools.
I didn’t entirely teach myself, I read some tutorials (I’m afraid I can’t supply specific links, google dodge and burn retouching and find a method which suits you!) But a lot of it is all down to experimentation to find a retouching style and work flow which works for you!
Hope this helps you some. :)