Hello!
I am making a pizzabox in Blender, the problem is, when i add the textures with UV Mapping it shows the images on both sides of a plane :
How can i turn that off? that it shows only on one side?
Either have a different face for inside and outside of the box or use a node material with two textures and a Geometry node set to give the different texture for the front and back face.
This is assuming you are using the Blender renderer. For the Cycles renderer there is a similar node for front/back
So… How do u copy a face, on the exact same position as the one u copy it from…
Select face, shift+D and move.
A real pizza box is made of cardboard. This cardboard has some thickness. I assume your model has no thickness, therefore the more you move away from reality the more faking you have to do. You could make your box have thickness (manually or with solidify modifier) as well and add different materials to different faces of the box
Well, i managed to make it thicker, and get the faces right.
Now i am trying it in Cycles render so i can use HDR,
The only problem is, i selected a face, but the texture still applys to the whole mesh 
EDIT: I managed it…
Now the problem i have, im making a sign, but when i place a texture on it, its flipped like it has to say STOP but it says POTS …