heh... well.. i'm just a beginner artist as well... but my hands start looking a bit more realistic after i practiced a bit

a problem with most people is that they tend to overlook detail completely.. its not really a bad thing.. but when you want people to know straightaway what your drawing.. you probaly need some level of detail

Take each part of the hand into isolation.. maybe you could draw grids on a picture... then cut the squares out... and then just draw grids on the sheet you intend it to be on, then draw the picture square by square

its tedious, but thats called practicing..

hope this is useful to you, and maybe i can look forward to seeing your art pieces one day