For espresso machines the grind should be between a medium and fine grind, or 20 to 25 seconds in the grinder. The best grind for coffee makers with a cone filter is a fine grind. Grind the coffee for at least 25 to 30 seconds. A fine grind is also used on vacuum pot coffee makers. If you have a plunger pot or a bistro, grind the coffee for approximately 10 to 12 seconds for a coarse grind.
Great coffee starts with great water.
Use fresh, cold water. If your tap water doesn't taste good, don't use it. Just as important as the water is the coffee. It has to be fresh and it has to be stored properly. Make sure that the coffee pot, filter holder or whatever it is you are using to brew your coffee is clean and rinsed well.