Well the modelling is well done, my only suggestion in that department would be to put those grooves along the cockpit into the normal map, they're too shallow to need to be on the model itself, and that would free you up enough polies to make the cylinder 24 sided, rather than the 16 you currently have. Also the raised ribs along the front guns don't need to be on the model, nor do the indents in the bomb tubes.
The design itself isn't bad either, it's one of those rare EU designs that manages to fit mostly into that Star Wars style. There are a few things that make it stand out though:
1) The giant engine at the back just doesn't really seem to fit in with the rest of the imperial designs. It's even bigger than the rebel engines. I'd come up with a different propulsion system, maybe make it a TIE-style (yes I'm aware that it's supposed to have one engine, not two, but it's the EU so it's fair game for redesigning)
2) The solar panels on all of the TIEs have at least one flat, greebled area. There is a small circular greeble which is present on every single TIE,
this one, And I think it'd help to break up the shape of the wing a little, make it less polygonal.
3) The way the wings connect to the body doesn't seem very imperial either. I'd suggest replacing it with something along the lines of the TIE Advanced, which has a cylindrical bridge attached to a flat plane. This would give you more opportunity to add some detailing into the texture as well, with more to draw inspiration from.
4) A minor one, but one that you made on this model that doesn't appear in the original references, the cockpit of every TIE has the ribs every 45 degrees, starting from perfectly horizontal and vertical spars. Yours are offset 22.5 degrees, so there are no horizontal or vertical spars. I think it would work better the original way. In addition, if you want to make the cockpit glass identical to the other TIEs (this is something I'd suggest) there is too much forward protrusion. See
here.All in all, my biggest suggestion for you, if you're looking to get your stuff in our game, is to start small, get one model up to our standards and totally complete before tackling multiple projects. Many suggestions we have will be on such things as your modelling or texturing style or method, and so they'll likely apply to all models you make. Save yourself some frustration and get one done the way we need it so you don't have to go and redo every model you've made.