Looking for product/project management help!

What have you done to validate your business model?

As a fellow developer who's had similar problems I can give you my prospective and what worked for me.

First off, it takes time, the more projects your work on the easier it gets to start thinking about them in terms of tasks/stories/whatever. It also gets easier to make estimations for things like time and level of effort which further helps with planning.

In terms of strategies I like to think about things in terms of components. I do a lot of work with React, so its what makes sense to me; I think about what my UI components are going to be and those end up being tasks. I then have additional tasks for the backend stuff that wires it up. I do full stack, but like to think about them as two separate streams of work to keep things organized.

I've always been a big fan of trello and Kanban boards, especially on small teams. Matching up my tasks with card, and then dragging them across the board gives me a good sense of progress and let's everyone know what's still on the list. It's also not too much overhead to quickly create cards, some software I've found to take up way too much of time. I'd prefer something quick and simple for a smaller team.

Another big thing I struggled with was making my tasks too big. I'd always err on side of caution and rather have too many tasks than too few. This is especially the case for more formal settings with things like code reviews where you're not trying to take in too much at once. It also helps with things like testing and catching bugs too as you're not trying to juggle too much functionality at once.

This is sort of a loose answer, but I think project planning can be a bit a fluid. Try to think about components, break it up into small pieces, but don't be afraid to bend and break the plan. I'm also not a master planner by any means, but I've delivered multiple projects on time so I like to think I know at least a little bit.