All I can do is offer suggestions based on how I first shaved my head, and how I now maintain it.
You can do this all by yourself (I did), or you can solicit help. Depends on what you're comfortable with.
You're going to need appropriate
If you've got hair, you'll need to do some preparation, and messy preparation at that. You may not care now, but anything you can do to make clean-up easier will make a big difference when you're done.
Lay down drop-cloths. Put on a poncho to keep the hair off your clothes. If you feel more comfortable doing this while sitting down, choose a chair which will be easy to clean off.
You are going to be working on the back of your head. If you feel you need to see it, set up a pair of mirrors. I find using mirrors just makes it difficult to get my directions right.
Your first step is, using the scissors, to crop your hair as short as you can. 1/4" to 1/2" is good. Try not to remove any ears or other appendages while you do this. I cut my hair off while standing in the shower. The tile and porcelain surfaces made it very easy to sweep up the hair, and there were no clothes to worry about.
Once you've got your hair trimmed, it's time to give your head the once-over with the clippers. This is going to be messy too.
It's easiest if you have clippers with a guard or guide. If your clippers don't have a guard mechanism, you'll just have to be more careful not to get the teeth into your scalp.
You could skip the scissors and go straight to the clippers, but I wouldn't recommend it unless somebody else is handling the clippers for you. I started out with very long fine hair, which invariably got into the mechanism and jammed the clippers after only a few passes. I disassembled and cleaned the clippers a half-dozen times before I decided to crop the remaining long hair with the scissors. No jammed clippers after that.
At this point you probably resemble a marine recruit who just had an appointment with a drunken barber. Don't worry, it'll all be gone in a little while.
I personally prefer to shave while I'm showering. Less fuss, less muss, and I don't have to listen to it.
I'm serious about that.
For some reason, the sound of the razor going over my scalp just annoys me. The sound of the shower drowns that out.
Besides, shaving in the shower makes sure your hair (that 1/16th of an inch of it that's left) gets wet, and is easier to cut. Getting your hair thoroughly wet softens it much more than soap or cream would. I have perhaps cut myself shaving 3 times since I started using a blade razor. I attribute that record to shaving while showering.
I've got photographs set up to display in a second window. The figure links will take you to the appropriate photo at the appropriate time.
So, once you're in the shower and all wet, take that soap (or whatever) and get your scalp covered (figure 1). I used to use Dr Bronner's Pure Castille Soap (in any of its scented varieties), but I've since switched to Neutrogena for Men "Skin Clearing Shave Cream." While water alone does provide some lubrication for the razor, you'll want more, particularly the first few times you do this.
If you feel you need the mirror, use it, but you'll only be able to see your face. Don't worry. It's much easier to navigate by touch once you get started.
Make sure you have a nice sharp razor blade. Hair seems to be much harder on razor blades than whiskers. Just let a woman use your razor to shave her legs, and you will see how quckly the blade can dull from mere hair. I have found that I can get about 3 good shaves out of a blade before I start having difficulties with it; when I just shaved my face I could go for weeks on a single cartridge.
Start by drawing the razor from the center of your forehead (on your hairline, of course) to the center of your scalp. This will give you a reference point to work from (figure 2 and figure 3). Rinse the razor blades. Rinse the razor blades after every pass, or they will clog (another reason for doing this in the shower).
I hate to look like I'm doing a product endorsement, but I've been using the Gillette Mach 3 razor for a while now, and it's been a major improvement over anything I've used before. Could it be the triple blades? Nope. The spring suspension? Nope. The little lubricant strip or the rubber fins? Nope. The new blade design leaves nearly the entire back of the blade exposed, so it doesn't clog like other razors I've used.
Work down one side of your head, drawing straight back with each pass, until you get down to your ear (figure 4). Repeat for the other side. The front half of your head should be done at this point.
Shaving the back of your head is easy. Just place one finger so it's along the top of the razor cartridge, and follows the path of the razor (figure 5). You'll be able to feel where you've missed, and go back if necessary (figure 6). Start at the nape of your neck, all the way to one side. Draw up and behind your ears, until you reach the completed area of your scalp. Work across the back of your head this way until you've reached the other ear.
Don't rub the back of your head until after you've rinsed it. The stubble you've cut free can can be very abrasive. You don't want itchy red scalp because you've sandpapered your head.
Rinse off all the remaining soap residue and stubble. Run your hands over your head, moving in several directions, feeling for spots you may have missed. At this point you can just carefully run the razor over those small areas for a final touch-up. Then, you're done (figure 7 and figure 8).
How much mileage you get out of a shave depends on how fast your hair grows. I can usually go two days without showing too much of a shadow, but beyond 3 and it starts driving me crazy.
You can (but I wouldn't recommend) do a quick touch-up with a normal electric razor if you don't wish to shave every day, but I've found I have more problems with ingrown hairs when I do that.
In the past, a gentleman never went out-of-doors without his hat. It's still a very good rule to follow today.
Buy a hat. Buy several. You're bald by choice, and I'm assuming you want to show it off. A hat, though, is no longer mere fashion, or something to hide your baldness. It's protection.
In winter, a good hat is vital. You lose a lot of body heat through your head even with hair. Since there's no hair to insulate you anymore, you need a hat to make up for it. A good knit hat or cap will function nicely. If you want to be more stylish, the Clearwater Hat Company makes the best 18th and 19th century fur-felt hats to be had. These are designs directly taken from the days when gentleman always wore hats, made with actual antique tools and blocks, so they're very comfortable and sturdy.
In summer, a good hat is vital. Few things are as painful as a sunburned scalp. Few things are more unpleasant than peeling scalp as the sunburn heals. You don't need skin cancer on that carefully shaved pate (just think of shaving it while it's sunburned). Oh, and don't forget that old "solar panel for a sex machine" joke. You can absorb just as much heat from the sunlight through your head as you'll lose during the winter. Don't increase your chances of sunstroke. Straw hats, from Dobbs or Beaver or any number of other manufacturers, are light and airy, and usually cool. Clearwater makes a large-brim straw hat which is just fantastic.
These suggestions apply at all other times of the year too. It's really convenient having a collection of hats appropriate to any weather, to keep the sun off, the warmth in, or the rain off.
Other frequently asked how-to questions:
How do I keep my head nice and shiny?
How do I keep my head from getting shiny after I shave it?
I get these little bumps/pimples after I shave. How can I avoid that?
The "Neutrogena For Men" line has a bunch of shaving products. Their "Razor Defense Daily Face Scrub" is an exfoliating scrub; use it (or any other exfoliating scrub) before shaving and you'll find that it reduces flaking and may prevent bumps or pimples.
"Neutrogena For Men Skin Clearing Shave Cream" has a small amount of Salicylic Acid (the active ingredient in some over-the-counter acne medications). It's an effective shave cream, it can also reduce bumps or pimples, and may also reduce shine (if that's an result you're interested in).