The internet changes all the time, each time getting bigger. A major way to get traffic for a site is to use a lot of social media sites (they don’t require optimizing your site for SEO) but SEO (Search Engine Optimization) is still a guaranteed way to build up passive free traffic from places like Google, Bing, and Yahoo.
SEO is really good for long term traffic. Don’t expect to get much from search engines until your website has a LOT of content and has been around for a bunch of time.
It’s important to have as many backlinks from sites that have better traffic and alexa ranking than you. Think of it kind of like as a referral and if you get a referral from a place that’s more important than you then that is a good thing in the eyes of the big search engines.