With no bugs or fungus to infect newly pruned branches, winter is the perfect time to shape your shrubs and make sure they are healthy. Plus, without leaves, shrub shape is much easier to see in the winter months.
First up, if your shrub is a spring bloomer, like rhododendrons forsythia or lilacs, pruning will mean less or even no blooms for you come spring. So it's best to wait on spring-blooming shrubs until after they bloom.
But all others are good to go.
Before you begin, make sure your pruners or loppers are clean.
Then start by checking for any broken or damaged branches. Prune those first.
Next search for crossed branches or branches that are rubbing on each other. The rubbing can create damage and encourage disease come next summer.
Suckers coming from the ground and vertical branches, called water sprouts should also be removed.
If you wish to thin or control the size of the shrub, cut out the oldest and largest branches near the ground.
To prune, cut at a 45 degree angle just above a bud. The cut should be 1/4" from the bud. Any more than that and you encourage rot. Any less and the bud may dry out.
Add shrub pruning to your winter garden to-do-list!