Different Shades of Chocolate

• Use different shades of chocolate icing to create a contrasting look.Dynamic Graphics Group/Dynamic Graphics Group/Getty Images
  
  You can accomplish the look of multiple colors on a birthday cake simply by adding more cocoa to some of the icing, thereby creating different shades of brown icing. Ice the cake with the lightest shade of brown icing, and then pipe on accents and writing, like "Happy Birthday," with a darker shade of brown. Make sure the shades have enough contrast so the piping does not blend in with the base icing.
  
  

Ganache

• Pour chocolate ganache on the top of a chocolate cake.Brand X Pictures/Brand X Pictures/Getty Images
  
  Ice the chocolate cake with a light brown chocolate icing, and then pour a chocolate ganache over the top to create a melted chocolate look. Once the ganache has set, you can pipe the words "Happy Birthday" on top of the cake to make it more personal. Don't forget to pipe a border on the bottom of the cake after the ganache has been poured so the border does not get ganache drippings on it.
  
  

Colored Accents

• Pipe a small amount of colored icing without compromising the flavor.Siri Stafford/Lifesize/Getty Images
  
  Ice your chocolate cake chocolate icing, but use other colors as accent colors. You can pipe on small decorations with white or tinted butter cream without compromising the chocolaty flavor of the cake. Alternatively, you can add multicolored sprinkles on top of the cake to give it a colorful accent. If you really do not want to stray from the chocolate theme, use white chocolate-flavored butter cream for you accent, as white chocolate can be tinted.
  
  

Yummy Additions

• This cake uses fresh sliced strawberries as a bottom border.Brand X Pictures/Brand X Pictures/Getty Images
  
  Decorate your chocolate cake with other yummy additions, such as chocolate-covered strawberries, chocolate sandwich cookies, peanut butter cups, malt balls or chocolate shavings. The possibilities here are endless. Choose an accent that complements the flavor of the cake, such as coconut for a German chocolate cake. Get creative with the way you place the items on the cake. For example, you can line the outside of the top of the cake with chocolate-covered strawberries or use peanut butter cup crumbles as a bottom border for your cake.