One technique I have used that not many people are using is e-zine advertising. There are many list owners who run e-zines in many different niches who will willingly allow you to advertise to their subscribers. This is usually by solo ads, classified ads, or ads between the content. Some list owners allow you to write original content for their list free of cost.
To find e-zines to advertise in, you can do a google query search for "your keyword" + newsletter or "your keyword" + e-zine. The best place I recommend going to advertise in e-zines is the directory of ezines at Directory of Ezines (not an affiliate link). There you can find different e-zines by niche and list size.
It can be very easy to make money quickly by e-zine advertising, but make sure to do your due diligence before booking an advertising spot. Check out the newsletter and see how many ads there are per content, how often the newsletter is sent out, how big the list size is, etc.
If you are looking to increase your traffic I would recommend looking into this strategy. What are some methods you are using?