Unless you are trying to create a hedge, prune individual shrub branches one at a time. Prune down to a side branch an inch or more inside the shrub. If the branches are too thick, remove some branches all the way to where they start. Shorten upper branches more than lower branches so the shrub is tapered in as you go up. You may not need to prune lowest branches at all. This taper allows more light to reach the lower branches so they do not lose their leaves and become bare. By pruning branches down inside other growth, the stubs do not show. Pruning to a side branch keeps the same thickness of branches, whereas shearing multiple branch tips causes three or more branches to grow from each pruning cut, creating an artificially thick growth. If growth is already too thick from previous shearing, removing entire branches will restore the plant to its natural thickness. Winter and spring are good times to prune shrubs with insignificant flowers or summer-flowering shrubs. Wait until after bloom to prune spring-flowering shrubs. You might as well enjoy the flowers first.
If you would like help pruning shrubs, give me a call. I can prune them for you or teach you how to prune them yourself. There is no charge for an estimate.