I do spreadsheets. A bit AR, perhaps, but it works for me. Start out listing all the general, big-picture tasks: "remove engine"; "rebuild front suspension"; etc. Once you get to that point, then I start breaking down each task involved in the operation. So if I'm at "remove engine," I'll start listing all the tasks I need to perform -- remove front bumper, remove apron, remove radiator, etc.
When I complete a task, I move it to the top and change the font color to green. I keep that spreadsheet active and updated, and I print it off (not the whole thing, just the "active" section) before I go into the garage for the day or evening. That way I have a list in front of me that keeps me focused on the task at hand, and it also allows me to cross the tasks off the list as I complete them. I use that marked-up list to update the spreadsheet and the process continues.
Breaking things down to "bite-size" pieces is the only way I can tackle big tasks. If I go into the garage armed only with the goal of "restoring my Triumph" I'd be lost.
I also use the spreadsheet to keep a running tally of parts I need. That way, I hopefully keep ahead of the game and avoid work slow-downs due to backordered parts, and it also allows me to take advantage of buying parts when they are on sale.