Awesome biceps and triceps

Really good! - I think the 3D effect would be stronger if you weakened the reflected light slightly. You can look at Stan's example for inspiration; note how the shade and shadows are clearly darker than the lights. - It would be nice if you took the photo straight on. When you take the photo at an angle, you get distortions, which makes it harder to critique. Hope this helps :) Keep up the good work!

The first one is good, the second one not as much. James Gurney always says that he recommends new artists, who are just starting, to avoid style and concentrate on depicting the natural world as close to real as possible. Your cross-hatching, even though it might be your preferred method for rendering shadows, is interfering with the depiction and understanding of the forms. I will add that, if you want to depict shapes and shadows through cross-hatching, I recommend Alphonso Dunn's videos on YouTube, and also his book "Pen & Ink Drawing: A Simple Guide". I hope this resources help you in your journey.