You paintwork looks good to me. Maybe just hit her with a gloss or semi-gloss overcoat and then a pin wash. Or maybe a sludge wash, I'm not sure which would be better for that scale and picking out those zillion teeny-tiny rivets would be a royal pain. 

And remember she's probably have mud smeared all up the sides and I think the tracks would carry it up and dump it down as well. You'd be well off finding some good photos on the internet and using them for reference. 

Ok, I continued with this method. Thanks for the confidence builder  I used a fine brush. Here's how it turned out. Tomorrow i will clear coat it and put on the decals. Then do some "mudding"!

The paint looks good. I don't know much about Great War tanks but the brushwork came out really well.