Crutches: A "How-to" Guide

Description
There may be times in your life (say, after a severe ankle sprain, a broken bone, or surgery on your foot) when walking on one of your feet is just simply not an option. At times like this (since self-propelled exoskeletons haven't really been fully developed yet), using crutches may be the best way to keep you mobile. You might use crutches to keep weight entirely off of one foot (and maintain your balance while doing so), or you might use them to support most of your weight while you stand up, sit down, or otherwise change positions. They may seem kind of intimidating and awkward at first, but with a little practice, you'll be able to navigate your way around pretty well.

First off, you'll want to get a pair of crutches that have rubber tips at the end (these give you a better grip on the ground as you walk around-slipping on crutches is not pleasant) and that are adjustable. (Those old-time crutches that look like a strange sort of branch (think Tiny Tim) are rustic looking, but won't work nearly as well as the more modern sort.) Your podiatrist can recommend places for you to purchase your crutches. (In addition to being a savvy doctor, he or she is also a savvy shopper for medical supplies.)

Adjusting Your Crutches
When you get your new pair of crutches, the first thing you'll want to do is adjust them so that they fit your height and body measurements. You'll want to do this while standing, although you may wish to get extra balancing assistance from someone else.

Start off with the tips of your crutches positioned about six inches to the side of each of your pinky toes. The crutch pads (those cushy, snack-cake-looking things at the top of the crutch) should be positioned right about an inch and a half, or about the width of two fingers, below your armpits while your shoulders are nice and loose. Don't lean on the crutch pads, either while walking or just standing around. This will put too much pressure on your nerves and may even cause some problems with your forearm strength.
Once you've got that adjusted, you can fiddle with the handgrip (the bar in between the crutch pad and the leg of the crutch) so that as you grip it, your elbows are slightly bent (about fifteen to thirty degrees, if you're into measuring angles). Your elbows should be able to extend fully when you take a step with your crutches. Many crutches come with padded handgrips, or you can cover them with padding in order to make them more comfortable.
Finally, the full length of the crutch should stretch between your armpit and about six inches ahead of the tips of your shoes.

Walking
Beginning to walk with your crutches may seem tricky at first, but should become easier with practice.

Start by creating a tripod with your weight-bearing (or 'good') foot and the bottoms of your crutches. (Just try to channel those alien world-destroying machines you see on movies, or envision a triangle with your good foot as the bottom point and the two crutch tips as the two top points).
Put the tips of the crutches about four to six inches ahead and to the side of the front of your shoes. (Again, envision that triangle.)
To move ahead, lean forward a little and move your crutches up another few inches (about four to six), and put your weight on them (through your hands on the hand rests, not through your armpits), moving your injured foot together with the crutch tips.
Then, while the crutches are still bearing your weight, move your uninjured foot so that it's now ahead of the tips of the crutches.
Bring the crutches forward again, and repeat (until you reach your destination, of course-then you can stop).

Chairs
Getting up and down from chairs isn't so bad. You'll want a chair that's stable, with nice back and arm rests to use as props. Also, avoid chairs with wheels on the bottom; crutches make them a bit skittish, and they tend to be evasive when you try to sit on them.

Once you've found a chair that suits your needs, back up to it so that the backs of your legs are resting against the edge of the seat.
Then, lift your injured foot up ahead of you and grab both of your crutches in one hand (holding them by the handgrips will probably prove most effective).
Reach behind you with your free hand and find the chair's arm rest, then lean on it as you lower yourself into a seated position. (Use your crutches in the other hand to provide balance and extra support.)
Getting up is pretty similar: scoot to the edge of the seat, then, while gripping your crutches on your good side, raise yourself off of the seat using your free hand and the arm rest. Once you're up, set yourself up again tripod-style, and you're free to dash around again.

Tackling the Stairs
Stairs are probably one of the most difficult things to navigate while wearing crutches. (Unless, of course, you're trying to climb a frozen waterfall with crutches. That's extra and especially tricky, and is also NOT recommended.) But there are a couple of methods that should make it possible to get up and down safely.

The safest way might be to employ kids' preferred method: going up and down on your bum. To start out, lower yourself onto one of the lower steps.

If you can, toss your crutches up to the top of the stairs, or put them as high up as you can reach. They won't be useful during the climb (unless you use them to poke at passers-by).
Put both hands behind you on the next step up, and lift your bum onto the next step, using your good foot for added strength. Repeat until you reach the top!
Going down is pretty much the same: put your crutches as far down as you can reach, put your hands behind you (on the same step as your bum) and lower yourself down a step.

If climbing stairs on your rear end is simply unbearable, you can certainly try climbing with crutches. Always use the handrail. If there's none available, you may have to resign yourself to the bum method. Also, if you can, try to rope someone into being your balance-aid as you go up and down the stairs. It'll make you a bit safer, and will give them points for helpfulness: a win-win situation.

Put both crutches under the armpit that's on the same side as your injured foot. Use them when you'd normally put weight down on that foot.
Put your 'good' foot up the step first, then make ample use of the handrail, your crutches, and any handy neighbors to keep your balance as you lift your injured foot up to the step. Keep repeating until you get to the top.
Going down, put your injured foot ahead of you along with the crutches. Then hop down one step at a time on your good foot.

Once you've mastered these maneuvers, you're pretty much good to go on the crutch-walking front. You may wish to hold off on marathons and dancing, of course, but, if you give your injured foot the rest it so badly needs, you'll likely be able to get back to unaided walking soon. And as fun as crutches are, they're no substitute for full mobility.