Looks great. I love this forum, wish it had been around 10 years ago as I would be 10 years ahead of where I am now.
Here are my suggestions.
1.) Try to remove the wash from the machine gun. These were oiled/cleaned/cared for much more frequently than the hull and turret, suspension, etc...
2.) Drybrush the machine gun and really the whole tank with a metallic shade to give it more of a metallic appearance. Keep it subtle!! I like silver cut with raw umber oil paint.
3.) Take you xacto and very carefully poke tiny holes in the decals, then hit the decals with solvaset. This will help settle them down quite a bit.
4.) Add "stuff" to your M-10. Pictures of these show they were most often loaded down with sandbags, logs, equipment, rations, whatever they could get a hold of.
5.) The wash you did looks pretty good, but I would do another, darker wash. Not quite black, but maybe a burnt umber. In particular, on areas like the suspension, antenna, hull, etc... This will really give the small details the chance to jump out at you.
Hope this helps. Really a super build... I have two Academy M-10's and an AFV club M-10 in the "to-do" stack...
Scott Gentry