The pricing, physical presentation(staging),photo essay, the description of your property and the posting(syndication) of that listing on the internet are the keys to successful marketing. If you can do that yourself and handle contracts, negotiation, disclosure, etc... cool.
If you use a professional take the time to interview a bunch of agents. The more you talk the more you learn about what to be concerned about and what to look for among the agents you talk with. Don't rush - talk. Keep your ears open. Take notes.