hmmm no one has posted any tips so here's mine- do not be offended :)
1-from the ground up that base needs work. GW is fine with green paint but CMON is a far fussier crew. See the shine coming off it? That little shine likely cost you a point right there. Invest in static grass or even some sand you can paint. I got 50lbs of sand for $3 at the hardware store
2- The orc. what orc? lol sorry just kidding, but he is out of focus and hidden behind the banner. I mean you could have the best painted orc face and we'd never know. hmmm Judging from the hand you got the basics of skin down which is good. Learning some highlighting and washing techniques will make you much happier though
3-The banner is what I CAN see and can rate you on. You did a great job of bringing out the grungy gorey bone and skull. Likewise a nice rusty look on the sheild. But the actual banner is begging for a device- some sort of unit symbol perhaps. It is too much flat area and looks kinda grainy/fuzzed like some dust is on it?
Like I said don't be discouraged with my critique- you are above table top cause you are trying to bring out the detail.