List to do according to priority. (foremost imortant things)

1. Make sure any kind of MONITORING is in place. (If not buy it by discussing it with your manager)

2. Make sure all the databases in the environment are BACKED up. (At least full backup but should suffice the SLA)

3. At this point i would recommend you to DOCUMENT all the database servers, this is really important to understand the environment before doing any changes to it. You can refer http://www.brentozar.com/archive/2013/01/documentation-it-doesnt-suck/