When stripping down a bike it is VERY important to tag and bag all the bits and pieces as they come off. If you are disassembling something get some paper toweling and pace it on the bench , then lay out in order, the pieces as they come off . then be sure to take a picture of them laid out. later you may not remember the sequence. with something like down tube shifters pull off one side and keep the pieces together then wrap them with blue masking tape which will keep them together . Take all the little bits and put them in plastic bags. Front brake, rear brake in separate bags. All the head set bearings , washers, nuts etc go in one bag. All the bottom bracket bits(left cup and lock ring, bearings, plastic dust cover if it has one, spindle, and crank bolts/ washers) in one bag.
Be very attentive when you remove brake and derailleur cable . Make sure to save the end caps on the cables. There are often special cable ends that are stepped where the rear derailleur cable is attached to the chain stay. loose that and you may not be able to get another one.

Get a large cardboard box and put all your bags, jars, etc. with parts in them in it along with everything else you take off the frame. When you remove the cables and covers label the covers so if you need to cut new ones you will know the correct length.
don't take the drive side bottom bracket cup out unless you absolutely have to. just lay the frame down on the work bench and Squirt some mineral spirits into it followed by a paper towel till it is clean. Bearings and races should be soaked in mineral spirits, then using a compressor and air nozzle, blow all the old grease out of them.

The frame can be first wiped down with wd 40 or mineral spirits . next, using white polishing compound, thoroughly rub out the paint. This will remove ground in grease, dirt, and anything that is on the paint and will bring out the color . It is amazing how much better a frame will look after a thorough cleaning and rubbing out.

When removing old cabling , inspect and save if it is still serviceable. Often the rear brake cable can be reused at the front , same for the derailleur cables.
I always put small parts in a large jar filled with white vinegar and let soak over night. Surface rust will then just wash or rub off with a tooth brush . Aluminum brakes will come out looking almost new, the vinegar being acid will lightly etch the aluminum

Front and rear derailleurs will be left to soak in a mineral spirits bath.

all small parts will be washed in Dawn dish soap and water using a tooth brush to get into nooks and crannies, dried, then sprayed with lemon pledge wax and wiped down.