There are two kinds of winter gardening.
The first method usually starts in January as the gardening catalogs begin to arrive in the mail.
This type of gardening is as easy as sitting in your favorite chair, browsing the catalogs, and either dreaming about what you’re going to do this spring, or actually drawing designs for the gardens you intend to work on.
The second type of winter gardening is to actually get out in the yard and do a little work.
Of course if it’s bitter cold, you’d be better off waiting for a good day. Winter is a good time to do some pruning if the temperatures are around 30 degrees or so.
I don’t recommend pruning if it’s considerably below freezing because the wood is brittle and will shatter when you make a cut.
One of the advantages of pruning during the winter is that you can see much better what needs to be cut out and what should stay.
At least that’s true with deciduous plants. The other advantage is that the plants are dormant, and won’t mind you doing a little work on them.
It is your job to decide how you want the plant to look, and then start pruning to achieve that look.