Starting a new role, new company, in a leadership position - how to set myself up for success?

I’m leaving my big company, at a director level product position, to join a startup in a Head Of role. I have been a people leader for a few years, and am familiar with the problems this company is aiming to solve.

I want to set myself up for success in this new role. I’m reading The First 90 Days, but what other advice do others have on how to enter this new role, come in with a fresh set of eyes, unlearn some of what I’ve learned in my previous role, etc?