As Photon440 stated, pictures are one of the keys to a successful restoration.
The other key is to break it down into sub projects and decide what level of restoration you are doing, as this will help you to get things lined up as you progress and to get a cost on things like paint & body work, chrome, upholstery, engine & drive line rebuild, etc. You also want to do it in stages, strip down, parts gathering, restoration or replacement of small items, major items like body work and engine trans building, etc. I had the body work underway while I was getting the suspension, axle and engine started so it would be ready for assembly once the body work was completed.
If you are going to strip down the car, then get a bunch of zip lock bags and a sharpie to bag and tag stuff and some small boxes or something to organize all the stuff you remove, and take pictures as you take things off, there is more stuff you will find as you disassemble. I used some small boxes organized by engine, body, interior, trim, engine compartment, undercarriage, and suspension to store the many bags full of stuff.
Use a spreadsheet to manage and track the cost of parts and labor, your time if you want, and status of your various sub projects. Make a list of all the things you will need or want to restore, replace, rebuild, or upgrade. You can organize the spreadsheet in much the same way as the parts being removed, however, I broke it down by systems, including engine, transmission, body, interior, fuel system, heating & cooling, axle/driveline, brake system, exhaust, wheels & tires, etc.
Don't forget to also factor in the small things like, hoses, belts, gaskets, nuts, bolts and screws, bushings, and weather stripping!!!!
Don't forget to factor in the costs of supplies, like solvents, paints, sand paper, tools, adhesives, lubricants, de-rusting solutions, dust masks, etc!!!! These things add up quick!
Always expect the unexpected!!!! Scheduling and delays in parts orders or work that is outsourced to others will have an impact on your project. Know what your budget is going to be, and try to follow it as much as possible. Unforeseen issues with the car itself can also impact your plans and progress.
When I started I thought I would be done in 2 years, but it took 3, and I went way over my budget. It was a lot more involved then I had imagined, so I hope this helps you a bit.