I typically don't use loose chopped strands, but the application is not much different than the cloth or mat application that you're used to. The only trick is to ensure even coverage/thickness over the parts and molds. Then you need to pay attention during the brushing of resin so that you don't dig out a thin spot in the loose strands of fiberglass.
This is why I usually stick with thin chopped strand mat. That, and the fact that my local supplier doesn't tend to carry loose strand fiberglass.