I am currently filming a movie with my brother and there is a scene that needs a stadium, what i am playing to do is build a model is blender and then get the angles i need a blue screen the characters in.
What i was wondering is does anyone have any tips to make the stadium look real? especally for the shading and materials

When you shoot your brother shoot a light sphere as well. Then use that as your light source in blender.

If you don’t know what a light sphere is, it is a a completely reflective sphere. Have you ever gone to a home and garden store and noticed the (usually red or green) balls that people put on pedestals? If you can find a silver one, you are set. Simply take a hi-res digital still of the ball. It will contain a speherical representation of your environment. You can then unwrap it and use it as a bitmap light in blender.

If you have not looked into HDRI lighting, Do a search and read up.

Having your brother lighting and the stadium lighting matched will get you a long way. I would suggest setting your green/blue screen up outside and shooting him there. Then setup your light sphere and shoot it at the same day in the same space.

Also, try typing in “budget filming” on google, there are forums just for that.