All professional coffee makers (baristas) will have their own technique for making the perfect cup of coffee. Here my home-grown suggestion...
The whole process begins with simple water. This water has to be good or no amount of decent coffee grounds will matter. Water should be fresh and piping hot. Water should not be stale, contain mildew, and be unclean and not properly filtered. The perfect temperature is just about at boiling point.
Now for the coffee-- choose any coffee that is grown above 3000 feet above sea level. There are many varieties-- Brazilian, Bogota-- my favorite is espresso. It should be pre-roasted, fresh within at least three days and smell good.
Robusta is one type of coffee that some people use for espresso machines, but it is not the best because it has very little flavor and way too much caffeine. It is considered an easy to grow plant and fairly disease resistant than other coffee trees.
Coffee should be ground in what is called a burr. Burr blades are pyramid in shape and have plates with two teeth that force the coffee to be ground in between. Coffee types like French or Viennese roasts are darker and are best chopped in grinders. Grinder blades chop only.
The fineness of the grind is determined by the space between the plates. Good-sized grains are the size of sand. Avoid grains that resemble dust or gravel. Be quick when removing ground coffee from a grinder. Too much exposure to the air makes it oxidize and absorb nearby smells. Garlic infused coffee would be horrible!
A great cup of espresso requires a top and clean quality espresso machine, or the experience is not worth it. What does this mean? Without a 9 bar pump pressure or more, the machine will be unable to generate thermo block or boiler heat to properly stew the grinds. The boiler will heat the water to the right temperature. Avoid steam-pressurized machines and be careful not to burn yourself.
The next step is to make the coffee! Warm up your machine and clean it by running fresh water through it. Simply turn it on, allow time for the water to heat up and flush the system and warm the inner surfaces by pouring a cup of water instead of coffee into it.
Now carefully add your grounds and slightly pack them down like you would with pipe style tobacco. It should feel slightly springy, but it should not move around suddenly when you remove your finger.
Put the hopper back into the machine in a firm manner. Warm your espresso cup and stand it underneath the outlet. Press start and in less than five seconds you will have a shot's worth of piping hot espresso.
Cappuccino is easily constructed by heating a half-cup of milk in your microwave for 90 seconds until it froths. Add this to your espresso. Garnish lovingly with nutmeg, chocolate or cinnamon. I like all three. Sprinkle with brown sugar. Enjoy!