I think you should work a bit more on these. They aren't bad at all, and some are completely ok, but most could use a better knowledge of anatomy. The most common flaw I can see is that the actual palm of the hand is a bit short, and sometimes the knuckles look uneven. It could help to define one or a few of the tendons by the knuckles down the palm a bit. Anyway, you're well on you way, keep at it!