Congrats on finding gold :) I don't want to sound like a sales man for Market Samurai, but I recently went through their training videos (www.noblesamurai.com/dojo/marketsamurai/) and have been using the app itself to get better visibility into what people are searching for and how to rank better. A few quick thoughts:
* look for long tail search terms (still related to your content) with high SEO value; that is, search queries that have high volume and low competition
* for your broader keywords (let's say "nfl draft research"), you can find out which other sites are also specifically targeting that phrase. Once you know your competitors (esp the ones who outrank you), you can find backlinks that are boosting the competitors search rankings. Some sites are pretty entrenched and have thousands/millions of high authority backlinks, but many niche sites can easily catch up to the top 5 ranked search results
I've seen basic SEO research and work (putting keywords into your title, h1, and URLs, consistency, etc) work miracles in terms of free traffic, especially for longer tail keywords.