I haven't found any good articles in Google... Can you recommend something? Thanks. EDIT: It's a "NICHE" directory, not "NICE"
I have good success with a couple niche directories, so would be writing up something soon explaining how to promote and make success from them.
For niche directories you need to get active in the communities that cover your niche. You can drive listings, links, and visits from the various forums or groups that are in your niche. Of course, if you get links from the people who you've helped in your niche you'll start seeing search engine traffic too. Of course, don't forget to get yourself listed in all the various web directory lists out there. That will drive a few listings a month...and give you some link juice.
A great idea for you would be to rank memebers of your niche and give out a badge they can display on their site. Top 50 Widget Maker etc...Top 20 top 5 etc you get the idea. The badget can link back to the page on your site where you rank all the top players in your niche. Anyhow hope that gets the juices going!
You shall promote the niche directory to have a good pr, and then put it on niche directory list to get some traffic.