Google Adwords is the most popular method for traffic. Since they are the top search engine right now it make sense to advertise there if you can afford it. You bid on keywords to get your site at the top of the search when your keyword comes up. There is more involved but it's all laid out at Google. There are a lot of other sites that use this advertising strategy called pay per click or PPC.

The truth is, dear reader, that content overrules everything. You cannot make a success of a site unless you have the valued content there to begin with, as a foundation for your work. If that content is not there, nothing will come of it. If it is there and it’s valuable, the rest will pretty much take care of itself (aside from the physical aspect of site performance).
Web traffic is measured to see the popularity of websites and individual pages or sections within a site. This can be done by viewing the traffic statistics found in the web server log file, an automatically generated list of all the pages served. A hit is generated when any file is served. The page itself is considered a file, but images are also files, thus a page with 5 images could generate 6 hits (the 5 images and the page itself). A page view is generated when a visitor requests any page within the website – a visitor will always generate at least one page view (the main page) but could generate many more. Tracking applications external to the website can record traffic by inserting a small piece of HTML code in every page of the website.[2]