There are many tricks you can use to decorate a cake, including using an oral syringe or toothpick for intricate designs. Amy Machnak shows you how to efficiently frost a cake when you don't have a stand.
If the size allows, you can actually pick the cake up and use one hand to rotate it while you apply the frosting with a spatula using your other hand. Start with icing the sides of the cake, using a forward and back motion. One important note: always keep a bit of frosting in front of your spatula, so you don't pick up any crumbs from the cake. It's OK if you have extra frosting on the top of the cake edges, because you'll use it later to cover the top of the cake. After you smooth more frosting across the top of the cake, you're ready for more intricate decorating.
How to Decorate a Cake [Sunset]