If you have a custom home or a high-end home, things might be different. Otherwise, you should be getting offers that match price and even better.
And I agree. You will do better working with a Realtor.
For sale by owner houses always get low ball offers - that's why they sell for 50K less than an average house sold by a realtor...Hope you are not going that route - you'd be loosing money if you did that.
If, however, you are selling through an agent - it's time to sit down and see if your house was priced the right way originally. If it was, then you need to revise the marketing plan of your property with your listing agent - she/he need to be on all major websites showcasing your home, the house needs to be staged and you need to request to see how the house is presented in MLS (multiple listings system for realtors) - how many pictures are there, what's the description...All needs to be done at the highest level - and you'll sell...quickly too.
Hope this helps,
Beachfront Realty, Inc.