That Mitchell and Webb Look - Working from home
Make sure you do some research on shared office spaces nearby. Unless you have already worked from home for extended periods before, that might be one of the biggest challenges you'll face. With a shared office space, you also get to meet and talk to like-minded people.
Also, get some good headphones, for hangouts/skype calls.
Get out of the house. I've been a freelancer for over a year and have a home office and I can't stress this enough. There will be occasions when your brain will just not work and a brief trip to the coffee shop, coworking place, or just a walk can really refresh your mind.
Having a separate office at home has really helped me manage my work-life balance. When I enter my home office I'm at work and I'm focused on work tasks. The other two things that I've found most useful have been a chalkboard (or dry erase) and a nice desk chair.
Definitely figure out your tax/insurance situation early on.
Make yourself a work/free-time schedule and stick to it. It's tempting to say "I can work whenever I want", but this also means that work will always be on your mind. Drawing a clear line between work and play helps you to stay sane and allows you to switch off work-mode.