Remove any diseased, broken or pest-infested branches at any time of year. For most conifers, this is all the pruning required.
Wait until late winter or early spring to prune your bush. As with most bushes, if they are pruned in the late summer or fall, the new growth may not have enough time to properly harden off before winter.
Consider the cut before making it on a conifer. Conifers are unforgiving, says Bert Cregg in Fine Gardening magazine. "Think twice and prune once," he continues. Make sure you understand why you're making the cut before you make it.
Cut only a conifer's one year growth when pruning. This will help keep the bush to the size and shape you desire. Most conifers are trimmed in an apical form. Keeping this form can require periodic shearing.