Create schedules, set time limits. Print out a sheet with two statements in large, bold text:
1. Nothing beats growth.
2. Everything can be improved (later).
Driving growth forward is more important at an early stage than any big picture considerations. Give yourself the luxury of complaining about things you overlooked by surviving long enough to have the time to look backwards.
Create schedules that have clear spaces for thinking time / research, and the majority being execution time. Any "big picture" / "what's the best way to structure this" questions that come up during execution time, set a timer for 10 minutes to find an answer or reach a best guess / something that keeps your options open. After 10 minutes, write it down as something to figure out during thinking time, and then keep working. Switch to working on another task if you have to.
Understand that you don't have to find the best solution for anything. You need to find a solution that moves you forward.
I'm reading a little between the lines of what you wrote, but it seems that you haven't yet decided what idea/product to work on. Therefore it's impossible to focus on executing it. You'll find the execution comes more easily when you have something that needs to be executed.
Lock in on a problem that people have. Write the problem on the wall, and then focus on solving it.
Of course, the first steps of solving are researching, understanding and validating - but if you maintain the focus, you'll make progress.
Everyone falls prey to the idea research or content consumption crack pipe. I do. On a daily basis.
Here are two things that help with keeping it in check:
1. Break up your day into two parts.
A larger execution part. And a smaller research part. If it's not that time of day yet to consume content, get shit done.
2. Presume you have a month to live.
Anytime I fall into bad habits (not just procrastinating with research), I ask myself "Would I be doing this if I was doing to die in a month?". That's usually enough to get me moving.