A simple steel-chest seen from above... could almost be a tile. Perhaps it can give you some ideas?...

http://goto.glocalnet.net/richard_fhager/jascad/img/things/chest1.gif

It looks a bit blue, actually. I'm pretty sure steel would be a tad bit more grayish.

Here, I tried: http://img690.imageshack.us/img690/9176/finallyghs.gif

How do I divide the metal into sheets?

I think you could use more contrast  between the grass and the metal, as well as overall.

how about put some rivets inthe metal adn divide it up into sheets? Probably tone down the steel's reflection as well.

Also, it seems kinda weird that the grass grows horizontally on the walls. I'd at least change it so it hangs a little or something just to make it look more interesting.

Yeah, couldn't get texture right. How can I make it look more like steel?

Steel? looks like glass/mirror to me.