The one and only thing which can increase your traffic rapidly is doing SEO(Search Engine Optimization) of your blog/website.
SEO covers all strategies which will not only give you huge traffic but also High PR(Page rank).
@johnmicheal - Although on and off page SEO will drastically increase the amount of traffic so will SEM and SMM (when done correctly). As for Page Rank; it is pretty much dead to the general public (Last public update was Dec 2013). Unless you are working for Google where you can actually see the impact your changes are making, for better or worse, then chasing PR is kinda pointless. Especially considering the algorithims for PageRank will probably have changed atleast 8+ times by the time there is / if there is ever another public update to Page Rank. You as an internet marketer would be far better off to chase mozRank which some marketers would argue has alot more difficulty in obtaining due to how many ranking signals it carries.
Create the best content you can with the best products you can possibly offer. Your content is your best advertisement - if visitors love your content, then they will go back and spread the word to others. And if you wanna go for paid traffic, then get it from sites like SEOclerks.