Congratulations!  You just landed one of the coolest, most challenging jobs on earth.  Now what?

As you start your first day as a new community manager, remember you are moving into a house where someone else arranged the furniture, picked out the drapes, and invited their friends over.  Tread lightly for a bit. 

Here are three practical things you can do to start managing the community quickly:

1. READ everything you can.  Read the forum topics, comments, blog posts, status updates, community guidelines, Facebook feed, everything. Look at the photos or videos that have been posted. This will give you the flavor and tone of your new constituents. You'll be doing a lot of listening in this job.
2. Introduce yourself and share something personal. Post a brief intro message and let the community in on one interesting tidbit.  Don't overshare, make it very brief and friendly. And for Pete's sake, use a photo avatar. You don't want to be the Wizard of Oz behind the curtain.
3. Start building resources internally. You're going to need the support of every department if you're managing a corporate community.  Start building relationships before you need them---everyone from IT/development to graphic design to legal should be your friends and advocates. So don't stay at your desk, mingle!

One final tip: there's no crying in baseball. This job requires someone who can think on their feet, be resourceful, deal with slings and arrows effectively, suppress their own ego, and keep a cool head at all times.  It's a tall order, but you're not alone out there!