I’m not a pro either, just my 2 cents.
If the metal plate texture that you use is tileable, you could just increase the X and Y size of the texture in the Map To panel, so the diamonds pattern gets smaller. Right now it makes your characters look really small, the patterns are really big, compared to your characters.
You can make metal look more “metally” if you use some specular. I see that your texture is a rusted one, so you could make a specular map that controls where and how high should be the specular level (where it’s rusty, it should be black or dark grey - low or no specular at all; where it’s NOT corroded, it should be white or light grey - high specular).
You use a bump map to make it look more 3-dimensional, great! But be careful, it seems that there is some shadow information in the color texture, that in some cases may work against your bump map. If you use bump or normal maps, you should make sure, that your color texture only contains self-shadowing or ambient occlusion.
The DOF effect is either too strong, or it just don’t affects the further part of the guy on the ground, which ruins the FX.
Other than this I can’t say much, if you could show more frames, a little test video or something, then probably we could help you more.