Motohead -
Here are probably the best tips I can give you -
1. Research - Gather as much info as possible about the type of Bronco you want to build, a daily driver, good trail rig, rock crawler. Collect all the tech articles, pictures and other info you can.
2. Planning, Planning, Planning - This is key to any good project. I suspect that lack of planning out my rebuild cost me a few thousand extra dollars. A solid plan will give you a good road map that will guide you during this long process. This is not to say that you can change the plan. Write your plan down and try to follow it.
2a. Phases - Take it one phase at a time. A large project like this will take a while and if you break it up into smaller pieces it will be easier to manage. In addition to easier management of time, phases will help you budget the project.
3. Research again - Now that you have done some research and created a plan for you project you will most likely need to do some more research to find info about the new ideas you will have. Then update your plan with any changes.
4. Picture and more pictures - Like others have said get a digital camera. Consider it an investment for the project. Not to mention the other benefits of having one (trail runs, b-days, holidays, etc). Just when you think you've taken enough pics - take some more.
5. The tear down - Mark everything with what it came off of. This will help later for either reinstallation or identifying the part for replacement.
6. The beginning of parts ordering - Order the first group of parts you need. Refer to you plan to see which parts need to be ordered in this first batch. Remember to think about the area you are working on and what else may be happening in that same area in the future, you may be able to save some time and money if you do them at the same time. For instance, don't clean the frame and paint it just to turn around later and weld on new show towers.
The list could go on and on because the project is a large under taking but it's worth it. One thing that I would recommend is if you plan on sandblasting your frame is include as many other parts as you can when your rent the equipment. Nothing worse than having a bunch of smaller parts that you have to clean later when you could have done it with ease using the sandblaster (I speak from experience on this one).
Well, I'm sure you will have fun and I hope you have deep pockets. Enjoy!