1. Know the purpose of it.
2. Know what you are going to include on it.
3. Start simple - maybe start with doing a blog as a site first things like blogger, yahoo, and that are helpful.
4. Have some online policies. Copyright, does and don't. What to include and not.
5. Know what software you are going to use. I recommend either knowing HTML or Frontpage.
6. Get a webmaster and others to contribute to it.
7. Get as many involved with it.
8. Keep it simple. Too much flash distracts.
9. Keep it updated. Nothing like seeing a website that hasn't been updated in months let alone years.
10. Have Fun ...use it as a tool not THE TOOL but "a" tool to promoting your ministry.