I find more problems when I run Model 12s really hard. IMHO, they do best when run smoothly and just firmly. Don't panic - run one like you are just a firm master of the mechanism.
And just for completeness:
At the loading table with a Model 12, you drop the hammer by pulling the trigger. All it takes is close action and pull trigger.
Many folks are hanging a scarf or some other indicator from the trigger guard before they head for the line. It's a reminder to both the TO and the shooter that the Model 12 has to be checked at the line that the hammer is down. Take the "M12 indicator" off the gun, show the hammer has already fallen by pulling trigger, stow the indicator in your back pocket or other storage spot.
You knew that already, I would venture!
Good luck with that lovely hunk of steel and walnut! GJ