Make pages for your server on planetminecraft and on minecraftforum.net and make those posts contain lots of information, screenshots, videos, the IP, links to your website etc. Just cram as much good stuff in as possible and present it nicely, and it should catch people's eyes. Also make a page on minestatus.net and get your users to vote every day.
When thinking up the set up of your server make sure to think of an original-ish idea, as that way you'll immediately be the best server of that kind and won't have any competition. The original's of things are much often better and more widely used, eg Coca Cola vs. Pepsi, or Cadburies vs. Nestle etc. So think of an original idea that no one else has done and advertise it on these posts and you should do alright
