If you want to brew good coffee, here are seven simple rules for reference

A. Use freshly roasted coffee beans and store them for no longer than one week. It is best to use coffee beans that were roasted half an hour ago.
 B. Store coffee beans in a light-proof container.
 C. Grind the coffee beans before brewing.
 D. Before use, let the tap water run for a few seconds, then boil the water with fresh cool water that has just flowed from the tap, but not for too long and do not pour boiling water on the coffee.
 E. Use your preferred method—piston, dripper, or whatever—to ensure the coffee has adequate brewing time.
 F. Drink immediately after brewing.
 G. Remember to preheat the cup before pouring coffee into it.