Does anyone have a fave fly?
I think there are flies that you have success with and give you confidence that they will catch fish once you have sussed out how the fish are wanting it.
Many a time I have been asked what fly is catching and all too often I have shown and told people the fly and how I fish it and then watch as they put on a similar fly and strip it back when I have fished a slow retrieve.
For me and guessing local stocked fisheries
Black buzzers
GRHE
Pearly pennel
Basic damsel (gold head, marabou body silver rib and marabou tail) black, olive, white and orange)
Spiders in various styles.
Get a feel for the conditions, vary the depth and retrieve speed. Keep an eye on how other anglers are fishing and their success.