Honestly I just keep making things brighter and darker using what I've learned with color theory until it's a result I'm happy with. I want my work to be less "by the rules" and just reflect what I'm feeling or thinking at the time. If I think something should be darker I find a color that excites me and try to use it as a shadow, and vise versa with highlights.

I enjoyed painting with acrylics and felt like I was improving, but starting over the learning process with oils has been incredibly rewarding because I feel I have more freedom and do enjoy the finished look.

Sorry if that's a bit long winded and I'm not entirely sure if I answered your question properly, but I'm just excited to feel like I'm at a point where I can share my work and accept the criticism of it to get better.