CDC grannom caddis is a highly effective caddis pattern that works great around the globe. Of course, it doesn't have to be just cdc grannom caddis, you can play with the colours of the body, hot spot (or egg sack). For some people it could be useful to put white CDC on the top of the natural one, just to improve visibility.
When it comes to fishing these flies, first observe what real insects are doing. If they are skating, you skate, if they are naturally drifting, just drift them.
Unlike bushy flies that can twist your tippet, this type of flies doesn't do it... so you can use thinner tippet if needed.

One tip... use extremely long tippets and watch how the dead drift improves with it....

tight lines

Vladimir