We always followed the same recipe silbram 17 posted but we added a couple of Tablespoons of white syrup (Karo was all we had for years) to the recipe before cooking started.
Some key things I remember. If you mix the cocoa powder with the sugar, then add the milk, your cocoa will mix up better. Add the Karo after the milk is stirred in. Try not to stir the mixture after it comes to a boil, unless you have to. Stirring while the mixture is cooking or starting to beat the fudge before it cools down enough, will make it grainy. It's all about patience. If you are adding nuts to the recipe, add them right at the last of beating. Any earlier will give your beating arm a workout.
fyi....the recipe we used was from the Hershey Cocoa box except that we only used 1/2 cup of cocoa. We all like milk chocolate better than dark chocolate.
http://www.ehow.com/how_2205012_hers...ate-fudge.html