It's just going to be practice, recursion in general is annoying to think about. Start simple, have a loop you want to write instead of a recursive thing, write it step by step instead of trying to do it all at once.

I was implementing newton raphson a few years ago in SQL (so as not to implement it as a straight loop) and iterating over the problem several times really helped.

Get a query. Now think of the next step in the iteration, and you're basically writing a query that connects to that. And now, it runs again and again based on the previous criteria.

If you can isolate each part of the query for each logical step you're going to have a much simpler problem to mentally solve.