I think the most important thing is to go bigger than you think you need...Make sure you have enough room for the birds you want to have and provide plenty of PROPER ventilation. (A draft is not proper ventilation.) Patandchickens has a wonderful ventilation page you should read. There are many nice coops on here to review so research a little. One of my favorite threads was "What would you change with your coop" type thread and it was very interesting to hear the things that didn't work or they didn't like. If I have the link I'll post it for you. Good luck and HAVE FUN!
This site is a great place to start...and great to fall back on once you get going. So read up, ask a lot of questions, and yes, go bigger than you think you need. Or you will be doing what i'm doing now, and be kicking yourself in the butt the spring of your second year because you want more girls, but don't have a big enough coop
Honestly though, there is a TON of wonderful information here, just beware since you're new.. you will be overwhelmed!!! The best thing to know is that there are always amazing people here who are willing to help you through any crisis you may face along the way