It's great that you've tried and been able to use the Reilly's lines well to structure the face. But you see, the lines are intended as a guide to help artists locate the flow of the facial structure and features, but not to replace the natural flow of the face. Our face has their own natural flow that you can only observe if you draw from actual people's faces. From what I see, I can only guess that you draw these from imagination, that you end up with stiffer looking portraits rather than gracefully flowing ones. To balance technicality and aesthetics, I will advice you to use the imaginary Reilly's lines on real life or photographs of actual people's faces. The other is to rely more on Loomis lines (lines dividing heads into three one-thirds from: hairline, nose, and chin), for general measurement and proportions, because it looks to me like the proportion of the faces are a bit off.
Nice work. What I would suggest is to practice some perspective and simple form drawing. Anatomy is great, but your line work seems a little hesitant and the perspective of the face at the bottom left isn't quite there. The eyes, nose and chin area should be parallel. Focus a little more on those two things, simple forms and perspective, and you'll see a big leap in improvement. I know because I was in the same spot! Good luck
Hey Valerio! Nice job on these, you're getting some really solid structure and gesture. The proportions are great, and I can't see much wrong with the anatomy that wouldn't be too hard to fix. What I would say, is that the drawings are generic. What @Erik Gist would say to students when I was taking classes with him is that everyone goes through set phases when drawing. The 1st step is a beginner where you're learning the ropes. The drawing aren't great, but there's massive improvement because you are learning so much so quickly. Step 2 is the generic phase where you have a decent (but not masterful) grasp on how to draw. You can make drawings that look like people consistently. Step 3 is where you start injecting your opinions on image making into your drawings. What I'd say is you're on step 2, which in my opinion is the hardest step to get past. The ways of getting past that phase vary depending on the person, but what has helped me is trying to draw with more confidence. I can give you a critique on some proportional stuff that's off here and there in your drawings, but that's stuff you'll figure out on your own if you just keep drawing more. The only advice I can give is to draw with more intention and confidence, if you do I suspect you'll see massive improvement. Great job, and good luck.