After you're done baking the cake, use a bit of frosting in a very thin layer to cover all the cake right down to the plate or cardboard base it's on. After that dries, ice the sides of the cake first, leaving a high amount near the top. Smooth the frosting out by turning the cake and keeping the knife or spatula at 45 degrees on the sides. The pile the icing on the top, and with a long knife or spatula, swipe the flat end of the knife right straight across the cake to make it smooth. Do this all around the cake until it's even on top. If you want to make professional decorating, your best bet is to have decorating bags and tips that you can find at a cake supply store. Sometimes you can put tinted icing into a zip-lock bag, cut a tiny piece of the lower corner of the bag, and squeeze the icing through it to make different designs. If you're interested in cake decorating (the way the professionals do it) and want to do it at home, try getting one of Wilton's soft cover annual cake books -- it explains in the back how to make the designs, tiers, flowers, etc.
Hope that helped you out some!
Moe
Hope that helped you out some!
Moe