Ruthlessly say no to most things. This is easier said than done pre-PMF of course.

Try to validate without building, before committing to invest into actually building something as indeed, it has a lot of cost on top of just development. It increases complexity both technically and conceptually.

create milestones. bound the scope.

if you don’t set and defend a finish line, you will never reach it.

you can always make additional finish lines.