You'll learn a tremenous amount just in the disassembly.

In disassembly, keep a digital camera handy, and take notes on each photo. When you take something apart that you are not familiar with, take its picture assembled, and take a note on that part (cable clamping, for example, on the center pulls, and the way the headset goes together. Subtle details, such as the order/placement of washers, bolts, etc are handy to know when you're putting things back together.

Disassemble over a large old beach towel, or carpet, or something that will keep parts from bouncing and rolling when you drop them. This will happen. Count on it. If you disassemble next to a car or table or bench, parts will automatically roll where you can't reach them.

After you disassemble and clean parts, re-assemble and lube, you'll be surprised how well they'll work. They're designed to werk when they're clean and lubed, and generally will.

Be sure to count bearings, in the headset, hubs, and bottom bracket.
Have ziploc bags on hand to put parts in.
Don't get in a hurry.
Note what's disposable, like cable housings, but keep the originals from which to measure the replacements.
When things get particulary frustrating, take a break, sleep on it.
Don't be afraid to slap your forehead once in a while.