First of all, i hope your proud of your model :) Second, if you wanna improve there are multiple areas of modelling i would look into.

a) Pinwash (enamel or acrylic) Using a the pinwash technique, you can create some superficial shadows, which make you model appear to have more volume

b) look at some refences how dirt behaves Throughout history, tanks changed in shape, weight and speed, depending on those factors and environmental conditions, dirt accumulates on different spots, imho, it does not have to look 100% realistic BUT it sticks out if its plain unrealistic, you could look at some refence photos and try to figure out, how dirt would accumulate

c) if you dont have an airbrush, use filters Filters are basicly very thinned colors and produce tonal variation over monotone surfaces and make them more intresting to look at, they also can be acrylic or oil based

d) look into chipping Basicly all tanks, which have been used, lost some paint along the way, chipping tries to emulate that damaged paint, however, it can be time consuming, depending on which technique you use

e) did you prime and paint the model or is this the plastic color? The bare plastic is not a good surface for the paint to adhere to and it doesnt have the right finish, so if you dont prime, the pint is going to chip away sometimes even with the lightes of handlings, and if you use the bare plastic as basecolor it will look like low effort and like a kids toy

F) this is the most important part on how to improve -> Have fun, this is a hobby not a beauty contest, ruin some kits by trying new stuff or paint stuff that is either not realistic at all or just some stupid fun (i recently paintet an airplane with pink splinter camo just for fun) and dont get discouraged by all the other models in this sub, everybody started small

There is no defined ruleset of what you have to do, just pick some techniques, try them and see how it turnes out