Before you start, it's good to list out your assumptions and risks. It's sobering. Then you can tackle your biggest risks, right?
Chances are you don't actually know your biggest risks.
The big risks are the unknown unknowns, and the only way to flush them out is to just do it. Then you're not just mitigating risks, but discovering them. That's why so many successful founders focus on execution. Not because they want to execute to their plan - but because they want to know where they stand sooner.
Tackling the fastest risks often flushes up the true risks sooner. So launch.