All good advice and definitely shooting from moving boat and fish moving then throw in the variable depth refraction issue to deal with also can give you fits, but have seen all of us suffer from CHS from time to time ...
Couple things we tell newbies or people having issues, if fish is facing straight at you or away from you is don't shoot at the fish, with the length of the fish as long as your left and right is good you'll normally have at least 18" or more of fish to error hi or low and still be in fish, where people tend to shoot high or over fish if facing away from you, aim about 6" at least low of the tail or once find "sweet spot" for depth and conditions your shooting you should be "in the fish" somewhere..
The right to left facing fish IMO are more challenging since you only have the thickness of the fish as a target vs the whole length of the fish....
But in reality the best shots I make is draw and shoot, If I shoot and think alot of times before I shoot I overthink it and mess up, compared to see a fleeing fish and draw swing and follow thru with the shot without even thinking, sometimes even amaze myself.....