How to Shrink To Fit (STF) your Levi's

Being a vocal and ardent supporter of Levi's, particularly the rigid 501 shrink-to-fit model, I get many questions about sizing and methods for shrinkage of said jeans. So many such that I feel it necessary to create a document to point to should anyone else ask.
So here it is, the definitive TBTYH guide to STF Levi's.
What we're workin' with.
A quick disclaimer, this is my proven method for myself. You may find it doesn't work for you because of your body type/size. If you're here because your thighs/butt are big, this should work for you in general. Some of my internet friends have reported to me that they've actually had to size up in 501s to accommodate their thighs!
Before you do anything, if you've never tried on a pair of Levi's or you haven't worn a pair in many years, get to your local Sears (I'm pretty sure most carry the standard indigo rigid 501s). Try a few pairs on to get a feel for how the pre-shrink waist will fit. Levi's recommends this:
If your waist is 27"-36", Increase size by 1"
If your waist is 38"-48", Increase size by 2"
If you want your jeans to still remain fitted after the shrink-stretch cycle, I would recommend subtracting one from each of those 'size-up' numbers. In other words, get your regular Levi's size for waist sizes under 36" and one size up for sizes over 36". If you like your fit a little slouchy after you wear them in, take the Levi's advice.

For the inseam, Levi's recommends this:
If your inseam is 27"-34", Increase size by 3"
If your inseam is 36"- up, Increase size by 4"
Once again, I would alter this advice. I favor a 31.5" or 32" inseam on most of my pants. I find that a sizing up two inches on the inseam of my STFs yields the best results for me. So unless you are freakishly tall or want a crazy tall cuff, I'd say size up two in the inseam. The caveat here is that Levi's only makes even-numbered inseam lengths. You'll have to deal with that fact. I can tell you that via this method, based on actual measurements of my jeans, that are tagged and measured to be a 34" inseam will shrink about 2.5 inches to ~31.5".

Alright, so you've figured out your size...oh great, you got a pair online in a color you like on crazy discount because Levi's has many periodic sales Now you're ready to shrink them... Aside: right now I am shedding a single tear for the "verde" greencast 501s that are now unavailable (don't worry, I haven't even started on my third and final pair). For this particular demonstration, I'm using a lighter brown pair of 501s. The procedure is the same regardless of color, however.

In order to shrink your jeans, you're going to have to expose them to water and then dry them. There is nothing magical about it, if your unsanforized denim gets wet then dries, the fabric is going to shrink, plain and simple, temperature of soaking and drying be damned. Conventional wisdom says you will get maximum shrinkage via an ultra hot soak and a hot dry. 
If you have a bathtub, start filling it with the hottest water your hot water heater can generate (remember to engage the stopper).

Gather your jeans and turn them inside out. This will minimize the amount of dye that leaves the fabric during the soak.
Next, throw them into the tub of hot water. You don't have to wait until the tub is full. As long as the jeans are fully covered in water, you can stop the flow of water and take a break. One hour is usually good enough. If this is your first soak/bath, check the tub periodically to make sure that you aren't losing water due to a leaky stopper. You don't want to come back to a pair of jeans in an empty tub.

Break time. Make yourself a sandwich, grab a beer or two, chill out for a while. After an hour or so, your jeans will be well soaked through with hot water. Fire your hand into the scalding hot tub and grab your soaking denim. Heavy, huh? Get some kind of pants hanger that can support the weight of your 501s + the water they carry. I had to wedge a washcloth in one kind of pants hanger to increase the friction in order to hold the jeans up. Hang the jeans up for twenty or so minutes to drip dry. Essentially, you want to just get rid of the serious moisture on the outside of the garment.

After the jeans are no longer dripping, lay a towel on the floor of your bathroom, place the jeans on top, then lay another towel on top of that. A drying Levi's sandwich is what you're going for here. Warning: your towels may pick up dye from the jeans. Don't worry about this, as it washes out fairly readily.

Next, imagine you are squishing grapes between your toes making wine in Italy and step on every square inch of the towel above the jeans, with both your feet, at least twice. This squeezes the extra water out of the jeans and shortens the drying cycle.
Step in the name of love. No, I'm not always wearing denim.
Rip those jeans back right-side-in and repeat the foot-blotting procedure on the exterior of the jeans.

If you're gonna wuss out, hang dry exactly like I described to drip-dry or hang on a hook from the back-most beltloop. About a day should do it depending on relative humidity. If you're planning on truly shrinking-to-fit, strip down to your skivvies, seriously. Or more. You get better heat transfer going commando. Put on your jeans! Wear them proudly while very damp. In the Northern Hemisphere, this (December) is not a very pleasant time to shrink jeans. The best time to do this is late Summer, early Fall, in my opinion. Sometimes you have no choice, however. If you get the chance to shrink in warmer weather, go outside and take a walk or bike ride. This will greatly decrease drying time.

Some tips while wearing your awesome damp Levi's:
  • Avoid sharply bending your knees. 501s have a serious tendency to stretch out in the knees, especially if you do full, ankles-below-knees squats while the jeans are wet.
  • If you're working with a darker color (especially indigo), lay towels on any upholstery you sit on. Wet denim is very prone to transfer its dye. Towels are easier to wash than your couch.
  • If you run up against your bedtime or you're just sick of wearing damp pants, hang them to dry for however long it takes. The parts that take the longest to dry are the hem, the pockets and the fly.
After the jeans are dry, the process is complete. You've done it. Start wearing the hell out of your new Levi's.
Wearing the crispy cardboard jeans for the first time.