transition to day care

Ha
I can't believe that my little one is going to be 6 months old in just a month and will start day care... 😥
I know we still have time, but I wanted to start prepering him and myself for the transition. 
What worked well for you guys?
How long is the first day usually? Is it common to do just a couple of hours in the begining to let him get used to it? Should I just stay with him for a couple of hours on the first day and only leave him there by himself on the second or third day? Any advice and encouragement is welcome! Thanks Ladies!