I'll be the one to give honest feedback, no, this art is not up to the level of commission work. Practice shading, sketching figures, and composition. Take some painting classes and watch videos on composition and shading. Like most crafts, it will take a great deal of hard work and practice to advance your skills to the level where others will pay you for them.
First sketch the anatomy of the figure, then add details, then add color, shading and highlights. If you start with just coloring it in you will end up with unrealistic figures and proportions, as you have here, which will never transition to the higher quality portraits you are thinking of selling because you're not starting with good fundamentals. Bolster your passion for art with a foundation in the true skills so that when you practice, you're improving in the right way.