Blue Cedar pruning

This particular tree does not appreciate being pruned at all - recommendation is simply to remove dead branches.

I asked this question about the spruce picea pungens "Hoopsi" and was told that you can prune them a little in spring by nipping the new candles in half or nipping a third of the new candles off them. I would add I am a bit puzzled by your picture as I have a cedrus altantica glauca and it does not resemble yours at all and neither do the other ones I have seen of other people's in real life or on the web. My cedrus does have new "fingers" in spring that could probably be treated in the same way. ( I'm not sure if they are called candles on cedars).

If you want to know how to prune so that you do not affect the shape of the tree negatively I would suggest you try your local bonsai association who should be able to help.