I answered this in Yahoo Answers and this is what I responded with-

Answer:
I usually recommend a top down approach by breaking down the entire wedding experience into 3-4 different parts:
1. Wedding Ceremony
2. Wedding Reception
3. Honeymoon

From each of these parts you break it down even further. Wedding planning is typically 12 months and every month something should be completed or paid attention to. For example, in the first month you would probably want to ask yourself general questions in order to know the answers to questions that will come up eventually such as how large you want your wedding to be. Just from answering this one question, you can determine the answers to other questions such where your reception will be located (if you have a lot of people, you would want a bigger venue... if you have more people, you would need a bigger budget, etc.)

Guides that help break this down for you will help keep you the most organized, but I hope this answer helped to give you some direction in your planning process.