I haven't been as into cocktails as I used to be (having kids and getting older curtailed it), so it's been a long time since I've tried to replicate the cocktail experience I've had at bars.
I don't know if I ever tried to directly replicate cocktails that I've had in bars. I mostly just focused on picking recipes and then iterating on them until I got them dialed in. It's a fun place to just explore.
What I did learn, though, is that almost all of the craft cocktails I see on menus are really just variations on a few basic classic cocktails. They'll give it a fancy name and tweak a few secondary ingredients, but in general, if it's got whiskey, it's often a variation on an old fashioned or Manhattan. (City names are a clue for the latter.) If it has simple syrup and citrus, it's in the ballpark of a sour.