Here is a list of tips for extracting the best mocha-made coffee:
1) Water quality: make sure that the water from your tap is not too limy or rich in chlorine because this could alter the taste of the coffee.
2) Water level in the moka: if there is a notch orient yourself with that instead, if not present, fill with room temperature water up to the valve but without exceeding it.
3) Amount of ground coffee: lay the coffee powder down and level it out but without pressing it down.
4) Stove flame: keep a steady fire making sure the flame never goes above the base of the coffee pot.
5) Coffee ready: remove the moka from the fire as soon as the coffee spillage ends.
6) Before serving: the coffee should be stirred with a teaspoon while it is still inside the moka to make it as smooth as possible.
English
Italian 
German 
Spanish