I would suggest that you plough through old threads (what I painted in XXX month is a good place to start) to find a style that you'd like to emulate.
Then paint something, put it up on LAF and then ask for advice as to how to improve.
You'll get honest and fair criticism, which will help you identify what to address.

Alternatively, the vallejo model color website has a detailed tutorial on blending acrylics.