One thing that I find sorely missing in many teams is onboarding documentation. So when you come in, document everything that you need to do (required permissions, development environment setup, mailinglists, subscriptions) and how to do it.
Strangely, onboarding documentation does not exist in many places. I ended up creating new on-boarding doc for at least 4,5 consulting engagements and the managers appreciate that a lot.
Happened to me...