Congratulations on completing Digital Painting 101! Since I don’t know you, or your history with art, I’ve laid out two recommendations for your next step. If you already have experience drawing or painting, and you just want to learn digital painting, I’ll direct you to the “Let’s Paint” videos (process demonstrations). These give a high level overview of the painting process, including many different approaches.
If you don’t have any experience drawing or painting, I recommend starting in section 2 of the free library: Traditional Drawing. These videos are a nice primer on the concepts of pencil drawing from observation. I can’t overstate how important these skills are - and how much easier they make digital painting. In truth, Ctrl+Paint only offers a primer on basic drawing - I encourage you to go to the local library, or sites like Proko.com to learn this skill in-depth.