How do I make a mirror in BI or cycles? I have very little experience with materials. I am just wanting to experiment with mirrors in Blender. For example, What I am thinking is to make two opposite walls inside a cube both mirrors. Can blender handle that or even 4 walls as mirrors?
For Blender Cycles
Go to the materials tab, create a new material, where it says diffuse click and press glossy BSDF. Set the roughness to ~0.
For Blender Internal
Go to the materials tab, create a new material, tick the mirror box and set reflectivity to 1 or a high number.
This is for the most basic mirror which just reflects. To make a more complicated one, learn a bit more about materials for Blender Internal and for Cycles learn about the types of shaders and the mix node.