Always start with good chocolate; a good chocolate will have a “smooth melt” – no noticeable grain when melted on the tongue. Never add anything to the chocolate (paraffin, oil, etc.).
Break chocolate into small pieces, or buy small chocolate pieces. Keep away from moisture (i.e. steam) when melting. In an oven, put the chocolate in a bowl/pan, place in the oven and set the temperature to the lowest possible setting and close the door. Check every few minutes to make sure the bowl is not getting too hot. To test, place your bare hand on the side of the bowl. If it’s too warm to leave your hand there, remove the bowl from the oven with hot pads and stir the chocolate until the bowl cools, then return it to the oven if necessary. May want to turn the oven off & just let chocolate melt slowly in the warm oven. Be sure to stir chocolate fairly often as it melts.
Chocolate can also be melted in a microwave, but milk chocolate can scorch rather easily. Melt on 50% power or lower. You can also use a double-boiler, but this is lots o’ work. If you have a lot of time, you can put a bowl of chocolate in an oven with a pilot light & it’ll melt overnight (or thereabouts). A slow/low crock-pot will also work.
“Tempering” is the process of mixing and cooling chocolate to get it ready for dipping/coating candy. Stir in bowl, or pour into a cold electric frying pan or marble slab and make “S” motions through the chocolate. Continue mixing and cooling until chocolate feels cool to the touch. Dip or coat candies. When working with chocolate, your room temperature should be no higher than 70º. Chocolate can be re-melted many times as long as there is no moisture present and it hasn’t been scorched.