Get a few backlinks from other sites, for example, submit to bookmark related sites or other directories.
like everybody before me said, you have to build backlinks, but what i also do is try and add quality content whether it is by writing relevant texts for each category or when you add a website yourself, try and give a good description. If you have the possibility to control the length of description written by submitters, you should ask for a minimum of 50 characters at least