I think you did a lot of things the right way but probably went after a tough market. Students. Students are the most broke category and then comes indiehackers :). I would usually refrain from selling to these 2.
"A quick market-sizing exercise: there are ~110k law students in the US, ~25% of whom are in journals, and half of those are 2nd years. If I could penetrate even 10% of that market at $10/month, I’d be at $165k in Annual Recurring Revenue (ARR)"
Haha. This is a classic newbie founder mistake thinking all you need is a % of the market. We all have made it. Now you know. Market estimate should be made bottom up, not top down.
"find the connectors"
This is so key. If you are in a niche industry, finding the right connections who can open doors can be huge.
"Don't be a solo founder"
As a solo founder (even though with a small team), I couldn't agree more. I know having co-founders brings in risks of conflict etc but I am so ready to build a fresh team with cofounders who are thinking about the business 24-7 like I do. If you have a team like that and you work well together, that's a dream.
Tell us more about your next thing.