I just started a videogaming-niche directory. What do I do now to promote it? I have never owned a directory before so I am still enw to this type of site.
You promote it the same way you would promote any similar sites in that niche. Fill it with content that your users will enjoy, then advertise on other sites in your niche. Forums, blogs etc.
Submit it to other directories, drop a sig link in a related forum, comment on video gaming blogs, use social bookmarking, exchange links with relevant sites. Submit to niche directories.
Buy some links from some high pr sites which are sorted in the same category as yours, and exchange some links with similar sites with same pr as yours.