I recently when to a talk about tree pruning, and winter, right before spring growth, is when you would want to prune.

At this talk, I also came across these resources you might find helpful.

This one has a good diagram about where to make cuts, and talks about thinning vs topping: http://ucanr.edu/sites/mgfresno/files...

And this one is about fertilizing: http://anrcatalog.ucanr.edu/pdf/8045.pdf