Another way to act is with your business cards. I have written notes on the back of my card and handed them to businesses in the past, however I just finished making some stickers I can place on the back and hand to a business.
My current sticker simply says "Due to your stance on guns and gun control I will not support you with my business."
If I know of a business like CVS I will make a stop just to give this message to the management. If I stop for gas or food and am faced with a no guns sign I will present them with the message and leave. My favorite, forgive me if I've told this before, is to see a no guns sign after I've started refueling. At that point I will stand outside, knock on the window, and make them come outside to transact business. I waited on gas customers through most of my jr. high, high school and vo-tech years, so why can't they do it today when they won't let me in the door?
I have sent an e-mail and a printed letter to the NRA asking them to renew the rolling billboard program the had against Phillips/Conoco for an attack on CVS. I encourage everyone to do the same with the NRA and any other organization you are a part of.