I took a class in printing with George Tice, a great photographer, and one of the best printers alive, and I learned a ton from him. First, take really good notes. I have developed a short-hand for all the darkroom techniques I use; every print gets a series of notes in pencil on the back, on an edge which might get trimmed off later. Once I'm done with a session, I transfer all of this shorthand into regular notes in a print notebook which lives in my darkroom.
Another thing I learned from George was to pin my base exposure around the physical center of the print. This is the hardest part of the image to get to for burn and dodge adjustments without adversely affecting other areas. I then do all my adjustments around the edges(relatively speaking). I almost never dodge, but rather I try to use the times needed for the areas that might need dodging, and then burn the other areasback in, since I find burning easier to do repeatably than dodging.
Nest- practice. Generally, I will decide what adjustments are appropriate to a print slowly, through a series of work prints. I try only to make one or two changes per version of a print, so I will have experience with the changes I will keep from earlier versions. I walk through each step in my head to make sure I know what I'm doing, and I will do a "dry run" with no paper in the easel for particularly complex adjustments or prints. Practice making the shapes with your hands, and performing the movements with the cardboard or whatever other tools you are using. For tools, I mostly just use cardboard and my hands. Very occasionally, I'll make a mask from a test print of a given image; but most of the time, whatever I need to do can be done with only the simplest tools.
Finally, take a class with a master printer. I can't tell you how much my printing overall, and my grasp of good adjustment technique specifically, improved after I took George Tice's "Master Printing Techniques" Class at the Maine Photographic Workshops. I also learned a tremendous amount from Jim Megargee of MVLabs in New York. He teaches at various places- too many to name; but there are quite a few master printers out there, and they can all teach you something, if you look. There's no substitute for being in a darkroom with a master.
