Driving traffic to a classified website?

I have a classified website, done for 2 ago but too less time to care it so that it got daily 30 - 50 visit from search engines.
Can anyone suggest any good methods for increasing traffic for my classified website?

I have already done email Marketing and promoting on social networks.

In my experience social bookmarking, directory and classified website not easily ranked, but we always get much more traffic from search engine, I'm still working on my 10 social bookmarking sites and i got much more traffic from direct and from search engine.
I can say you one of strategy that you can follow for generate traffic. Just create 10/15 blogspot (different name related to classified) and create posts about classified websites..for an example of blog posts title: "Free classified ad posting websites" or "Best free classified ad posting websites" or Free classified websites list or top free classified ad posting website and etc, then share your classified website link on this post. After that you have to do some social bookmarking for created blog posts.

You know that every SEO guys finding classified sites, directory sites, social bookmarking sites using this type of words on every search engines.
Nowdays ranking not a stone or any weights substance/thing that you can easily move, you have to invest your time for that to get increase traffic.
I think you will understand.

Advertise on other classified site, create pdf share it, forum sig link, make tutorials in forum and target your site.

Facebook, sharing, twitter, start a good discussion on fb,twitter for your site.