Most times when you find yourself at a crosswalk, you simply stand in front of the "don't walk" signal, and the light will eventually say "walk." Sales can be a lot like that. You just show up often enough and someone eventually buys something.
At important, busy intersections, corners where some extra caution is required, you can walk up to the crosswalk and watch the lights cycle through for the cars over and over, but you just keep getting "don't walk." After a while, you'll look behind you and see there's an extra step you need to take to get across: there's a button you need to push to get the "walk" signal you want. It's an easy thing to do, but if you don't notice it, you could stand there all day waiting.