You're right about generic and high volume keywords having a ton of competition, especially if there's commercial intent for that keyword.

First - to find the best keywords I'd recommend using SEMrush or Ahrefs to find high volume keywords that have a lower difficulty score. The difficulty score is different from the AdWords competition score, and pertains to organic results instead of paid.

Like you mentioned, you should definitely target terms that people already are searching for related to your new terms you're introducing, and then introduce them to your new terms.

Like all marketing, repetition plays a big part. A benefit to you being the only one talking about it now is that you can shape the conversation. If you have email lists and social media accounts, you can actually influence the volume of searches for these new terms if your audience is large or passionate enough.

From what you wrote, you already know the strategy, you just need a good keyword tool to discover the hidden gems.