SCAR-L assault rifle

here’s some project im working on…

also, anyone could tell me what im missing ?
i know its not finished, the thing is im really bad at texturing and materials. and i think the material i use is really plain and boring. can someone help me how to make the materials look more realistic ?

a tutorial about texturing would be nice

here’s the wireframe of the main body (or whatever it’s called)

do you think it has bad topology ?