I've printed other people's stuff. It's a good learning experience, but I didn't really enjoy it.
1. Have the negative be as good as possible, in an effort the keep the printing simple and predictable.
2. An effectively dust free darkroom.
3. I agree on the instruction to visit museums, see the work of high quality masters, both living and dead. For silver images, seeing Karsh's portraits and Paul Caponigro's mixed stuff has been inspirational. A theme show with old masterful things is nice too (such as the pictorialism versus f64 show the portland ME museum of art had a couple years ago) Along with this, the print exchange (at least on lfinfo) is good for contemporary comparison.
For 35mm and 120 users, making fine negatives is not always possible due to inevitable compromises that are made at the time of exposure and development.
... and poor negatives make for a skilful printer who will really sing when dealing with good negs!
I understand what you mean. When I was shooting with an RB67, I had multiple backs that I would use for N, N-1, and N+1 development. I believe it is still possible, even with 35mm roll film, but it does take more discipline to carry it out---and this is easier said than done, I admit.
3 Show & discuss your work with others who's own work you respect and get feedback, don't work in a total vacuum.
I'm afraid I'm guilty of this one. There is just no one around me that does this or knows anything about it. So I have no one to share my work with or get tips from. Sometimes I wish someone regional would be willing to visit me and watch me work in the darkroom and offer suggestions. That'd be amazing!