Read The Magic of Thinking Big. You're not a wantrepreneur - you've tried something and been paid for it, and that's a big step that a lot of people don't get to.

Changing your mindset is the first step. Don't think that because you only have five hours a week to work on your project, that it is forever relegated to "side project" status and capped out at $100/month.

It sounds like you want to focus on web apps, many of which are heavily dependent on organic search traffic. The first thing that I'd do after reading the book is to get a SEMRush free trial - a lot of affiliate sites have 30-day free trials. Look at how many people are searching for your target keywords, the keyword difficulty score, what advertisers are bidding for the keywords, and traffic of comparable sites.

If everything checks out, look at how you can improve on the comparable sites. Everything has potential for improvement - even if your tool works exactly the same way as a competitor, just optimizing the website copy (do a ton of A/B tests and talk to your users) could yield impressive results.

Hope this helps. Good luck!