The problem with books is that they put to much info for you to think about between your ears. Anytime you start using that thing between your ears your shotgun shooting scores will go down.
Agreed.. The only exception, IMHO, for true newbies is to get the proper stance totally ingrained so that you don't even think about it at the line.. That takes a while..but once it's done, the rest is the result of instinctive hand/eye coordination and knowing your firearm..
As an example - I started playing pool at about age 12.. Played for about 15 years and thought I knew the game.. Did ok, but knew I was missing something.. Found a teaching pro in the Twin Cities and paid for lessons.. The first week, I learned one of the most basic things I was missing - the proper stance and angle of body/cue position.. That alone raised my game.. I was determined to be the best I could be at this game and took every lesson to heart - practiced sometimes 6-8 hours/day, six days a week.. After a few months the stance was automatic - never had to even think about it..
I applied the same techniques to trap/skeet...and the results were similar.. Much better overall scores and averages.. IMVHO, the stance is critical to good scores in shotgunning..
YMMV...