Regret to hear that your home is not selling.
There can be several factors as listed below:
1a.) You are priced high or at market price and there are too many homes to choose from.
1b.) You are on a busy street
1c.) There are just not that many buyers out there
2.) There is no curb appeal
3.) Home needs work or repairs
4.) There are short sales or up coming Bank Owned properties that will be priced cheaper.
5.) There is not enough exposure on your property.
Type in your home address on www.google.com and see if the property shows up.
6.) Poor marketing, is there a virtual tour, are there over 12 pictures
7.) Are you allowing Open Houses and showings.