I recently discovered a new decorating technique and I am in love with it!!
You layer different colors of buttercream around your cake (does not matter if it is a little messy), the take your cake smoother, or bowl scrapper, and go around your cake smoothing out the sides, which will combine the colors of your buttercream, creating a clean finish.
And then I topped my cake off with a gumpaste purple flower dusted with luster dust.