That means, first of all, that you have to be located near your customers or near an area where your customers are likely to shop.
In addition, you need to have plenty of parking and your parking lot needs to be easily accessible from all directions. There is a grocery store in my neighborhood that is only accessible via the northbound lanes of a busy street. The only exit is via the northbound lanes, too. So, it is really only convenient to go to this store if you are traveling north. Think of how much business they are losing because of this!
Easy customer access is even more important if you are competing with online stores for sales. Your customers already have to go to the extra trouble of getting dressed and leaving their comfortable homes to come and visit you. Don't make it any harder on them by putting up barriers to access. :)