bits i circled look really messy. those need a desperate cleanup. Plus the proportions seem off, you got some strange edges going on, the bed is just a bunch of flat stuff, so throw some bevels in there. Plus the rest of the body looks really flat in spots, especially the front end. every surface needs some depth.
As for the paint, there's no real flow. the daimondplate just sort of stops, the AO bake on the white bits is just overbearing. Makes it look like film grain: the truck, rather than selling it as paint. Also i'm pretty sure real lights aren't just big bricks of solid colour. So model the stuff in there or something, iunno
Try setting the AO to multiply at about 75% to fix the grain, other than that, yeah. Needs work