I think it never hurts to think about some of the things that might happen and make a plan for that - if you're offered a drink, if there's peer pressure etc.
It's often a good idea as much as possible to have a full glass.
I think it's also good to have an escape plan, so going in your own car and for a limited time is good.
and don't be afraid to put off your re-entry into society if you don't feel entirely sure you're ready.
D