Directories work differently from search engines. While a search engine will spider and index your page, analyzing it on different things such as keyword density and link popularity, a directory does none of this. Instead sites need to be submitting manually to them, and then also edited manually by an editor, who is either a volunteer or an employee. Once you are accepted into the directory it doesn't always mean you'll be getting good traffic right away. Instead it could take a wait of two weeks or more before the search engines that are powered by the directories update their listings.
I realize that this concept of a search engine being powered by a directory and a directory not being a search engine may be confusing to some of you so I will elaborate more on it. Search engines have taken to incorporating directory listings in order to improve the quality of their results. In some cases this means they spider sites in the directory as they would other sites but give sites that are also listed in the directory a bonus. In other cases this means that incorporate the titles and descriptions used in the directory into their own results. In other cases there are search engines that also run directories, not their own directories but rather they have an arrangement to use the directory from another service. Two examples of a search engine using a directory would be directory.google.com which is a modified ODP (Open Directory Project) directory, and AltaVista.com, which includes a version of Looksmart's directory.
To get a good directory listing you need to understand how they serve results. For people browsing a directory it is really nothing more than an alphabetical list. If your site happens to be listed in a category with many listings then if you're at the bottom chances are you will never be found. If you read my article on naming your site you'll remember I talked about having a name that would rank high alphabetically, this is the reason. The only way sure fire way to get ahead in directory lists is if you have a name that is ranked high alphabetically.