First of all I would like to say welcome to Armorama,and congrats on your first project in 30 years.I myself have never even tried a diorama,but yours looks good.As far as advice I would say that your tank looks glossy,perhaps tone it down with a matt finish,Also the lower hull,road wheels and tracks would look better with some weathering,especially for a diorama.But keep on building and I am sure the guys here will have some good advice for you.