Lots of good posts. It boils down to drawing every day. Yo mentioned underlays and overlays on the previous page. Tracing over your own work, or a CAD image or a picture is always good. The more you draw the better. Ask for people to look at your work…most are happy to give you feedback. Follow people on Instagram. I have learned/been inspired all the time from people I follow.
People ask me how I sketch on Canson/construction paper in pen without an underlay…the answer is simple, I have done tons and tons of underlays.
I am also a believer in CAD and Sketching as partners. Each pushes the other and helps improve the “other side of the coin”.