Keep in mind, Verve allows for a very different philosophy than ordinary digital painters. It's just a process of adjusting your habits. What happens in standard paint apps such as photoshop and the likes, is that one gets progressively stiffer and stiffer, working overly careful with layers and transforms and all those tools that turn it rather into a kind of construction than a painting. In Verve you best begin to free yourself, don't think in terms possible mistakes, very much like you would do in actual painting. You work with the substance of your painting, not with the construction of layered elements.
You can absolutely employ traditional procedures. That includes actually making a sketch in a different layer, but then all your painting itself can and actually should happen in one layer. It will free yourself, as much as you may not believe it right now. But once you recognize the liberation you will experience, it will activate different layers of your consciousness and with much greater ease will you create much more coherent paintings- nay- masterpieces!
Also, when you listen to advice such as "make something more gray" or something like that, be careful, because that's not the kind of advice that gives you understanding. If anything, this might lock you into unconscious patterns, procedures without awareness of why you would do such a thing. As a result you will not be able to deal with different situations, such as different light colors or even different types of skin, for example. Instead you must become aware of what you want to achieve. I was giving you already some hints in regards to the nature of skin (tissue thickness, layers beneath the skin tissue) and the nature of lighting and bounce lighting. Become deeply aware of translucency as well and you will really begin to know what you're doing. The more you understand, the better you can study, too, by looking at actual substances, people and so on. You will notice details, which totally escaped you earlier.
Work with your mind! Do not just absorb any "paint by number" information! Become aware!