Here's what I was able to dig up:

Prune conifers, such as pines, by removing a portion of the "candle". The "candle" refers to the candle-like appearance of the new growth on the tips of pines in early spring. Once the "candle" has matured, buds present on it usually will not develop and grow; however, removal of the tip of the candle before it matures can stimulate buds into growth.

The Colorado University Extension's master gardening site has a similar recommendation on their page for pruning evegreens.

I've just been shearing some candles (not recommended), pinching others, and leaving yet others alone. I think I just need to wait and see what happens now, but I'd love to hear others' experiences.