I agree with Bob that printing a lot, and in a short amount of time, teaches you more than most anything else. During my last year in college for a degree in photo, I took a job printing in a lab. The work there did more to improve my printing than any of my own projects simply by demands of quality, volume, and time. Printing my own photographs got much better during and after that experience, s when I got to graduate school, my printing was well beyond my peers.
Another thing I did to improve stemmed from a project I was required to do in grad school. It was designed to provide the means to choose what look you want for your work. I duplicated this assignment just this past month. I used one negative that printed well without dodging and burning (it still needs some for a fine print, just not for this) and chose two different papers (Ilford MG, and MGWT), seven different developers (Sprint, Dektol, Selectol, Selectol-Soft, Ansco 130, and Ansco 113 which is an amidol formula, with two different dilutions and times), then each of these was toned in a different toner (selenium 1:3, 1:9, and 1:19 for 5 and 10 minutes each, Kodak Brown toner, Kodak Polytoner 1:4, 1:24, and 1:50, reveresed Sepia I, and reversed Sepia II). This made a total of 196 prints to compare tonality, color, and contrast.
Bob, I will send you the prints on MGWT with the reverse sepia since you said in another thread that you had never heard of it before. Just tell me which developer you want to see it with.