If you really work for hours on a print, and don't realize it's wrong until you've completely processed and dried it... there's something wrong.
Evaluate the print at each stage in the process, after each decision you make. Always evaluate prints in the same place, at the same viewing angle, and under the same light source. Otherwise, you're constantly comparing apples and oranges.
Write down everything you do with a print. Fred Picker called it "the recipe". Start with the image size, the paper you're printing on, the developer you're using, development time/temp, etc. Write down your initial exposure time. Then add a note for each burn or dodge, until you have the print's recipe. Finish up with whatever toning you do with it.
If you evaluate the print at each stage of the process, you should never get all the way to the end, and realize that you're not even close!
If you don't know how you got to a certain point, and the end result isn't what you wanted, you have to start all over again, because everything affects everything else!