Looks like you have a good solid foundation and brush control. But first up, I'd like to address the photo, in and of itself. See how the center is in focus and the extremities are blurring out? Try doing the following,..
1) set your camera/phone to use its macro function.
2) If your camera has an aperture setting (sometimes called an F-stop), set it to somewhere around 16.
3) set your ISO as low as possible (usually around 100 or so)
4) use a backdrop. (the camera will try to focus on everything,.. the model, your hand, the paint bottles, and even the wall in the background. the backdrop helps to limit the "depth of field" that the camera sees, and makes its job of focusing on the model much easier)
Just do these 4 things, and your photos should come out far better. (There are more advanced things, like lighting methods and color correction software. But for now this should do. If you're interested in more advanced stuff, feel free to ask. I, or one of the others, will be happy to help)
