ESPRESSO
Entire volumes have been written about espresso preparation. Rather than a step-by-step guide, what's appropriate here is a handful of general principles, a bibliography, and sincere good wishes.

While the type of machine that you have is important, the grind is a critical part of the process in creating a tasty espresso. You must have a burr grinder that grinds evenly, and it must be easily adjustable.

The single most often repeated error in both home and professional situations is overextraction - too much water through the coffee. In a professional capacity machine, a 17 gram dose of coffee (double shot)should get you no more than 1.5 ounces of intensely flavorful espresso - any more than that and the syrupy goodness that is possible in a great espresso gives way to harsh, thin, brownish water. In a home machine shot volumes should be kept closer to one once.

The tamp should be firm - 30-50 pounds of pressure. The water must work hard to evenly extract the maximum flavor from each speck of coffee in the portafilter.

Brewing times should be around 25 seconds, in a high-quality pump-driven machine. If you get 1.5 ounces of espresso in about 25 seconds, your grind and tamp are about right. More coffee in less time, means that the grind should be finer and the tamp firmer. Less coffee in more time means courser grind and lighter tamp.

ESPRESSO RESOURCES

Espresso Coffee: Professional Techniques, by David Schomer.
Brimming with relevant geekage.

Espresso Coffee: The Chemistry of Quality, by Andrea Illy (yes, that Illy).
A chemical examination of espresso coffee that is only for the most avid espressophile.

Visit the Coffeegeek website.