They don't mind you packing in the bank?
My understanding is that a business must post a notice outside banning carry.
I rarely go into a bank.
I live in an open carry state, and am in and out of three different banks regularly with no problems. The only questions I've ever had were on the order of; 'watcha packin'?'. I do have a CCW, and CC most of the time, but like I said, no problems in banks. Costco on the other hand, asked me to leave the one time I open carried there, and they didn't have any signs at the entrance disallowing firearms.
I've been CC'ing for 20+ years and the best advice I can give is to: a) Use a retension holster. b) Wear it on a belt designed for carrying a gun. Those two things will make the biggest difference. The gun won't flop around, or fall out, and you won't be hand-checking, or adjusting it all the time. If it's secure, you don't think about it. If you don't think about it, you'll forget it's there. If you forget it's there, you don't telegraph that you're carrying.
Personally, I CC a Glock 21 (full size .45) in a Blackhawk Serpa holster, on a 5.11 stiffend nylon gun belt. It rides at 3 o'clock, FBI style (high and canted forward) and no one can tell, even under a light shirt.