Good, relevant and unique CONTENT.

Yes I agree, I think good content has a role to play

What kind of site? Good content is a start, but promoting that content is the next step.

Here are a few things that I often do to get traffic.
Submit your link to directories, maybe do some link exchanges. You might try google ad words depending on your budget. Maybe you could even start a blog and get your blog listed in various blog communities. Good luck with everything!!!

I agree with bolder. Content is king. Unique, quality content is all the search engines are looking for nowadays.

Social networking sites are good platform for generating targeted traffic, for better exposure join SN sites and go for tagging in bookmarking sites as well, if your good content does not get a path to travel then what is the use of good content?

Social bookmarking and blog is the good way to boost traffic for the site and the way to expose your links.

Content superb and updated is very important as well as presence in search engines with right keywords. With minimum knowledge you could start with SEO on your site.

Quality content with lots of back links...

If you done with content, make step on Directories submissions, classifieds, PRs and link exchanging. Mind the relevancy in all things.