Social networks for sure, create a page of your blog and invite people to like it. Forums related to the niche your blog belongs too, just go to the advertisement section if it has one and promote your blog there. Mail other sites or bigger blogs that are in your niche and ask them if they want to cross-promote or just promote you. Organize a giveaway if you have the means, this will create really huge traffic since people love free stuff. When you post something use appropriate key words, they mean a lot when talking about good ranking on the search engines. Also, check and see if your blog is indexed by Google, this is also important for traffic. Make some BTL (below the line) promotion for it, spread flyers with your blogs' address, make stickers and post them on everything you can. And ultimately, if you have the financial means, hire a SEO firm that can help you in this endeavor and optimize your traffic and all.