There are two ways to melt chocolate, in a double boiler or in a microwave:
1. Double boiler method:
A double boiler is basically two pots designed to fit together for melting wand warming fragile foods. The bottom pot holds a bit of water - never enough to touch the bottom of the second pot, the top holds the food, in this case chocolate. You should never place chocolate directly on a heat source, you run the risk of scorching it. Cut the chocolate up into small pieces, this will reduce the melting time. Adjust the heat so that the water in the bottom pot gets hot but doesn't begin to boil. Place the chocolate in the top pot and stir every so often. Dark and bittersweet chocolate are the most 'hardy' forms of chocolate, they will require less stirring than milk and white chocolates, which will burn very easily if you do not pay close attention.
2. Microwave method:
Place chopped pieces of chocolate into a microwave proof bowl and heat it in the microwave for 30 seconds. Remove the bowl, stir what you can then return it to the microwave for another 30 seconds. Continue this until the chocolate is just about melted. You might be tempted to increase the time intervals, but remember that warmed chocolate will keep its shape, even if it is melted, unless it is stirred. Don't judge time on looks alone. When the chocolate is almost completely melted, remove it from the microwave and stir, letting the warmth of the bowl and surrounding chocolate complete the melting.