I’m working on some inbound linking campaigns, so here are some ideas for you to consider:
Take a look at the Internet Search Engine and Submission Directory for a reviewed listing of directories accepting submission of your site.
Go to Google and use search for portals or directories covering your specialist topic. Here are the results for a Google search for “construction portal” or for a search for “arts directory”.
As you browse through the portal or directory keep an eye out for the Submit Your Site link.
Other directories you should take a look at: