Difficulty begins with the pattern chosen. Sine waves and starbursts are very simple, just a repeating color pattern with varying widths. Magazines such as McCall's and BH&G's Quilting give examples and directions. Expert examples include those in Joen Wolfrom's "Visual Coloring".
I learned to sew long strips into tubes, then cut the tube into widths, unstitch a square at the proper color point, and sew the resultant colored strips together. This quick piecing method allows me to do a simple pattern quite quickly.
This is a fun technique to play with. Good luck with your projects.