As you arrive by boat from Siem Reap, you will find many guesthouses' touts waiting for you at the pier. It is a bit confusing at the beginning, they shout and hassle you around...
Unique Suggestions: If you have a guidebook, take a deep look at the accomodations section while you are on the boat, before arriving. Decide then where to go. You will probably find a guy from the guesthouse at the pier, if it's a popular one. Then go directly for him and avoid the others.