I like the gritty feel you have given the tank. With the weathering have a look at reference pics of different vehicles and tanks. See where the water collects and creates rust that way or arid climates affects metals. Also give the rust a bit of tonal variation for added realism. If you wanted to improve a structural element I’d suggest looking up how to replace aerials with stretched sprue. The turret is very well done.
Looks pretty good from where I’m at. I’d say try to make your lighting more consistent and your weathering more random. Put rust in clumps and leave some areas more intact. Good job, keep at it.