When I was mainly shooting 35mm, I thought my exposures were fine. When I started shooting MF, I also started getting more critical. I learned that I have a tendency to underexpose and got fairly good at printing thin negs. I've since worked on exposing better to start with and it's gotten a lot easier to print. I think your negs may be on the thin side (tough to tell on the web) to start with, but you'll learn how to print for that. You'll also learn to expose a little more. One thing I do is to make a contact sheet using a "standard" time and conditions - #2 filter, f8, 8 seconds, enlarger height just at the spot so an 8x10 sheet is covered with the light in focus, 50mm lens. I can tell from a contact sheet if I over or underexposed.
I've also heard the "rule" that you should stop down two stops for the lens to be at its best - I don't subscribe to that. I think it may have been true with older enlarging lenses, but there's a reason they have more than just that one aperture. If I'm making an 8x10 from 120, I usually use f11 or f16. For 11x14s, it will be f8 or f11. Sure, someone with a magnifying glass and measuring devices could probably find "issues" with those using f16, but I seriously doubt anyone actually would be able to see a major difference at normal viewing distances. The smaller the image, the closer the light is to the paper, so the shorter the time needed, too.
Whether you're using a diffusing or condenser enlarger may make a difference as well (I've really only used a condenser one since I started paying attention to what I was doing). Also, use the contrast filters all the time. I use them for contact sheets, too. If you're using them, you can do a first try with a #2 and be able to try a quick print with a #3 or #1 without starting from scratch.
The more you print, the more you learn.