I've spent about 14 of the last 15 years working from home. Mostly full time but some of that was half in the office, half at home. First off, be prepared for a better life. The one
thing you can't get more of in life is more time, now you have more time since you're not driving.
Office with a door - Mandatory. You'll find that you'll always be "on" and that is bad. Telecommuters either slack off (and get fired) or work too much. I love my current setup, my current office cannot be accessed from my home, it has a separate entrance. So my commute is about 10 seconds of walking.
Hours - You'll want regular hours and stick to them. Again, this is to prevent overwork. It is also good in the begining to prevent goofing off.
Water Cooler - you don't have one. You will be out of the loop on everything that goes on in the home office. Oh well. 90% of that was crap anyhow. Missing the 10% can hurt you, but don't worry. You'll get by.
Perception - All of your co-workers will think you are goofing off. So you will be held to higher standards then they are. That's ok, they get to fight traffic on I-whatever twice a day. If you work 9-5 you are home at 5:00:01.
Headset - get a nice one. And I don't mean a $100 Bluetooth one. A $10 wired one that is comfortable is far better.
Pets - get a cat or fish. I have 4 fish tanks in my office. I'd love to let the cat in but with the walk outside that's just asking for trouble with her.
Enjoy your new life, congrats!