10. Rotate all the passwords immediately since the other guy has left the organization and have a password policy in place.

11. Understand the reason the other guy was fired make sure you are not the one holding the bag.

12. Have a issue tracking system in place, you will thank yourself later.

13. Have a change management policy in place.

14. Before you make any change full understand the consequences and have a tested plan to get back to a known good state.