In the start2finish tutorial, there's the part about wrinkles and seams. try that where you have your white lines. I think that'd work alot better. As for the belt and other stuff. I think comics2film has a tutorial on metals that might help.
No offence but it looked really good in the thumb nail. maybe if you were to try just one tutorial all the way through instead of takeing bits from this and bits from that. it is a good attempt.