What makes the best cup of coffee? There are several key elements:
1) Use clean equipment - dirty coffee making equipment will impart bad flavors to the coffee
2) Grind the beans just before brewing - preground beans will have lost some of their flavors
3) Use only the freshest roasted beans - once the coffee beans have been roasted, they will immediately begin to lose their volatile oils to evaporation, and it is these oils that contain the best aromas and flavors. Coffee beans that have been roasted longer than five days before will have already lost most of its flavor.
So the trick to making a good cup of coffee is to find a business locally that roasts coffee beans. Many small coffee shops do this. If you want to spend the money, and don't mind the extra fuss, you actually can buy your own home coffee roaster. Here's one example:
This is perhaps THE SINGLE most important key to a superb cup of coffee! If you buy pre-roasted coffee beans - even from reputable companies such as Starbucks or Gevalia - you will not be getting the best cup of coffee because they will have lost much of their flavor already by the time you use the beans due to the fact that the beans were roasted many days and even months earlier.
The roasting process takes the oils of the coffee bean and makes them sort of boil out onto the surface of the beans, where they are then quickly dried and roasted to adhere to the beans' surface. These oils are volatile, meaning they evaporate quickly. Because they've been dried to the surface of the bean, they don't evaporate as quickly as if they were still in liquid form, but they still evaporate at a fast rate. Within a few days most of the oil has already evaporated, taking with it the best flavors and aromas, and leaving behind the bitter tasting bulk of the bean.
The next step is to decide what kind of coffee bean you like. This is not something you can learn from reading about it, though. Everyone has his or her own preferences. Some like very dark flavored coffee, others light. Some prefer Arabica, others prefer Robusto. After many many years of trial and error, I find that I'm pretty much a Colombian coffee fan - which is funny since it's one of the most common coffees around.
When you're ready to make your coffee, take the beans out of where you've kept them (it's best to keep them away from air, but don't put them in the freezer or fridge!). Then grind the beans just before adding them to the coffee maker. You can buy coffee grinders at most department stores.
The rest is pretty normal. Use cold water (not hot tap water, which may contain impurities). But other than that, wait for your coffee to be done, add cream and sugar if you want, and drink it soon - coffee that's been sitting in the pot all day loses its flavor.