Some people like to use cream of tartar or other tricks for meringue, but it isn't necessary if you do it right.
Meringue tips can help if you're a neophyte or if you've had trouble before. Mostly, you need a dry day and no oil on any of your utensils.
Classic Meringues with Cocoa
4 egg whites
2.5 c. sugar
1/4 c. cocoa powder
Preheat oven to 200 degrees.
Beat egg whites to stiff peaks. Continue beating while gradually sprinkling in sugar and then cocoa. Pipe or drop meringue by spoonsful onto parchment-paper lined cookie sheets. Bake at 200 degrees, 25 minutes for chewy meringues or an hour for crisp ones. Drizzle with melted chocolate, if you like.

