I don't think you suck at all- those are incredible! I love the rendering on the one where they're looking up. However, what I would suggest is looking at reference of musculastructure, especially for the upper arms, but remember that there is skin over the muscles on the actual character (a trap I've fallen into many a time). I'd also suggest looking at individual refrence for the hands rather than trying to copy them from a full-body refrence, where it can be difficult to tell what's going on with the hands. The bridge of the nose could also be moved up to just between the eyes rather than below them in the profile. The back on the fullbody and the lower far arm look amazing though, and I really love the shaping on the profile (I'm a sucker for high cheekbones). The hair is also really amazing. Overall, just more reference and practice, and you're set :3

Short on time for any proper critique but you got amazing foundations! :0 You got a good clue about facial structure and muscles, and rendering's lovely to look at - really nstuff cheeks work bro :D