Learn some UX
I've transitioned from a backend engineer to a frontend engineer, and now working in mobile. Other than a basic wireframing course on design lab, i've never received any formal training on good practices, design patterns, and common tools of the design workflow.
I've know how to use sketch enough to draw boxes on artboards, and I've used illustrator enough to change colors on existing templates :P
Ideally, I can find someone who's willing to answer my questions via email on an irregular basis and give some feedback on some of the stuff I create.