Hi, thought I'd post on here seeing as I've just modelled some hand like this
1. There is only an extremely faint if visible at certain angles at all 'y' shape on the palm. Yours is too deep, and not smoothed enough
2. Your wrist is looks fine from the front view, however on the side view it looks way too slim - literally like a pipe, the wrist slowly increases in girth as it develops to your forearm.
3. Youve added some bumps on each finger in the middle, although these are there - there again very very small - yours are huge, smooth them down as they consist of wrinkles where the skin folds not bumps, lower them and sculpt some very faint lines (they tend to be straight lines but from afar can see a form of a circle.
Like others said, just stare at 1 section of your model, then contrast it your hand before moving on!
Hope this helps