Check out an agents websites and blogs. If they are difficult to navigate, then buyers will have a hard time finding your home in a search. However, if an agent plasters your home all over the internet in as many places as possible, uses videos and virtual tours, has a system for capturing buyers information and returns phone calls to buyer prospects promptly, then all is good.
With that being said, almost all buyers start their search online. But the next step is to drive by or ask to see it. If the curb appeal is lackluster, they may never pick up the phone. If the price is obviously wrong for the neighborhood, they will also skip over it. Price it as close to market price as you can, then expect your agent to fight for you when it comes time to negotiate.
The idea is to get as many people in the door as possible, so that you have more choices.
Another helpful hint is to use a stager. They can work wonders!