Gotta get better dawwwwwg
The texturing is incredibly basic(I am not even sure if this is unwrapped) and the mesh for the tank and the pilot bother don't look too good from what I see.
The mesh of the tanks treads look like it has a bad flow and is skewed a bit.
You should really try to improve your skills and get the hang of box modeling along with texturing. The box modeling will especially help with the pilot.
From an artistic point it really isn't that much, sure it is fan art but you haven't nailed the actual design and I don't think it compares to the original design itself.
You've really misinterpreted the design of the tank. The lines on the treads and wheels are examples of this. The proportions are noticeably different compared to the original and I really don't think you've captured the feel and look that it appears you have tried to do.
Look up some guides on texturing, box modeling and various other things you might have trouble with. It would be great to see an improved version of this that captures the feel of the tank logo.
Practice a lot more.