Hi, Wrath Warbone. This is one of the most asked questions, but it has a complex answer because there are several ways to drive traffic.
For the most part, search engine traffic has consistently been the best over because people are actively looking for information via the internet.
This is great for an online business or website owner because you can set up (optimise) the pages of your website or blog for the keywords that people are looking for related to your niche topic.
Several SEO companies online will offer their left leg to get you as a customer, but I recommend trying out a keyword software called Market Samurai.
It does a great job showing, explaining in simple terms how to do keyword research, developing a keyword strategy that helps keep your website staying up and ranking well on the search engines.
Plus, it has a lot of other cool features that can help you determine if a certain keyword would be profitable or not.
I hope that helps.