You can bake the best cake in all the land, but if you don't know a few basic cake decorating techniques then your delicious masterpiece won't get the attention that it deserves. A trip to the cake decorating supplies section in your local craft store or grocery store reveals a wide range of decoration options. You don't need to know any elaborate techniques to get started, as the basics will serve you well as you learn.
The first step is to learn how to smoothly put icing on a cake. The main problem that cake decorators run into with icing a cake is picking up crumbs from the cake and getting it mixed into the icing. It's actually pretty simple to avoid that. Never let the spatula touch the cake itself. Instead, rest it on top of the icing and gently spread it across the surface of the cake. You'll end up with a smooth and even surface.
Use a
piping bag, or a ziplock bag with the corner cut out, with various piping tips.
This allows you to create professional looking decorations without a lot of
fuss. If you don't have piping tips, even just cutting out the corner of the
bag gives you a few decoration options.
Click this link for more information on cake decorating supplies