I’m trying to make this look as real as possible. I’m sure there are a thousand things I could do to improve it.
Try to think about the direction of light, and what environment this object is supposed to be in. On a street corner? If it’s a reflective, metal texture, give it something to reflect! You’re going to need some key and fill lights to reduce the flatness of the red textures.
I would highly recommend Cycles to render this, because in my experience, blender internal just doesn’t have the realism needed for proper metal.
Details, keep on adding them. And there’s no such thing as a straight surface - and if there is, it doesn’t bounce light so straight it looks like it’s straight. Then add dirt, grime, scratches. Lastly work on the light.
But you’re absolutely on the right track. Very nice start. 
Put it into an environment and think about the color of sunlight, of the light underneath a tree, of the blue sky. Your model feels unrealistic because of its austere setting.
Not a bad model, I’d say the textures on the roof and side are a little too blown-out, they look almost shadeless. But don’t turn it down too much or it wouldn’t catch people’s eye (I mean, after all, this is a roadside stand. =D)
It looks like the client is happy with what I have so far. I did a little more work on it. Basically I just canned the reflection map texture and used raytracing.
I would love to spend more time on it getting everything looking perfect but it’s time to move on to the next project.
Thanks for your input everyone.
Feel free to comment on the updated images.
Attachments
Two things caught my attention, to add more realism. Stainless steel cart need that metallic look. It reflects quite a lot of environmental stuff. Here are examples:
And if you are selling pizza, you need a sign that can be read mile away! You can add lot more props as well; price list, different types of cheese, drinks…all kinds of stuff.
