To increase the traffic for the site you must do the blog commenting, blog posting, also try to do the link exchange to get some quality tyraffic to the blog. Also try to maintain the quality content on the blog.
Due to ink exchanges becoming more and more spammy looking, I would certainly advise against this. 3-way links would be a much better option.
that's depend on what's your site about, and try to add some unique articles or rewrite some articles, and choose the top social bookmarking like, facebook, tweeter , digg,stumbleupon