Do you mean two dries as in one dropper and one main point fly?
Just make sure the point fly is heavier so it helps turn over your leader easier.
So a size 10 on the point and a size 12 on the dropper. That kind of thing
Cast in an arc and try not to leave the fly still for too long. This increaes your chances of coverring a fish.
If your turn over isn't great, pull the line in slowly so both flies are in a line with your line (helps you strike into a fish)
Space the droppers a reasonable distance apart. 3 ft? This also helps you cover more fish plus its supposed to look more natural to the fish
Good luck