You could purchase an exposure meter for darkroom printing. I believe RH designs makes one.
Keep in mind that every time you make a change, and tweak something in your print, you learn something new, and that improves your skill as a printer.
The paper in the darkroom trash can are valuable lessons learned.
And, if you use the same film and developer every time, you will know a lot more what to expect come printing time, which saves a lot of guesswork and paper waste.