1. Properly grind beans just before brewing.
Coffee beans lose freshness dramatically once they are ground, so grind them just before you brew the coffee. Burr grinders, which use steel plates to evenly grind the beans, are superior to blade grinders, which unevenly chop beans, resulting in uneven extraction of flavor. Use a fine grind for espresso machines, a medium grind for drip coffeemakers and a coarse grind for French press pots. Beans should be used within four weeks of roasting; check packages for roasting dates. Store beans in an airtight container in a cool, dark place (not the refrigerator, where odors can seep into beans).
2. Don't stint on the amount of coffee.
The rule of thumb in brewing specialty coffee is 2 tablespoons of ground coffee to 6 ounces of water, regardless of the method of brewing. Better to dilute coffee that tastes too strong with a little hot water than to use too little coffee when brewing.
3. Use good water.
Coffee is mostly water, so the quality of the water is very important. Even if you have good-tasting tap water, it's probably a smart idea to filter out chlorine and other unwanted elements. If you do use tap water, run the tap about 20 seconds or so to let the stale water out of the pipes and to let in as much oxygen as possible. Always use cold water.
4. Make sure the water is hot enough.
The vast majority of home coffeemakers do not have sufficient power (at least 1,200 watts) to heat water to between 195° F and 205° F, the temperature required to make coffee properly. If the water is too cold, you won't get sufficient extraction and you'll wind up with a weak cup. If too hot, the coffee may burn. And don't forget: Drink the coffee within 30 minutes of brewing, and keep your coffeemaker clean. If you let the coffee sit, or make it in a dirty pot, none of these four tips can rescue it.