Hi. Does anyone know how to assign a materials to a face or something like that within an object in blender? Thanks.
select your face, go to edit buttons (F9) and in the ‘Link and Materials’ tab, press the add new button to add a material index to your mesh if the material is not yet present in the mesh.
Then press Assign and go to the Material butons and select the right material.
It’s quite cumbersome I know. I actually coded a menu which automizes all this behavior but as always time’s too low to implement it comletely.
I think this tutorial should be clear enough: Tutorials/Multiple Materials 
If you have questions or meet inconsistencies please post them here, the tutorial is a bit dated (Blender Version 2.31).
And if this tut isn’t enough here’s a second one.
Cheers,
Werner
Thanks for the advice. This will definitely help me alot!