I think I would vary the heights of the different colors, like doing an ombre balayage
DIY Ombre Cake Technique with Airbrush and Makeup Sponge - 17 Amazing Cake Decorating Ideas, Tips and Tricks That’ll Make You A Pro
How-To Base Ice a Cake
Tartas y Galletas de Cris - Excellent post on any and all piping - buttercream, royal icing, glaze
How to do brush emroidery on cookies. Can also be done on cakes, cupcakes, fondant, gum paste, etc. All you need is thin consistency icing and a flat brush.
Checkerboard Cake Decorating Technique - 17 Amazing Cake Decorating Ideas, Tips and Tricks That’ll Make You A Pro
Here's an Ombre Cake tutorial with frosting technique as published on the website momsandmunchkins.ca.
~Craftsy: Cake Decorating: History, Overview and Techniques.... lots of info but I picked pic I liked from one example: Cake Being Airbrushed with Sparkling Paint~
Simple Cake Decorating on Pinterest | Beginner Cake Decorating ...
Four simple but stunning cake decorating techniques!