I don't know whats happening in that pic, but its a very exciting and pretty something...
Just first impression, it looks really cool as a whole. The background is very nice.
Basically, make the beams more "powerful" by making them a bit bigger and have a white middle. The fighter bolts should be smaller and sparse-er. Also, try making them nonsymetrical, as in the left and right gun pods should't fire at the same time.
I would recommend re-doing the placement of the ships altogether. A few of the fighters looks ok, but the cap ships are too far off, and I don't know what that tringular thing in the top-right corner is. You need to make it either a "close up of a capship (not full view) with other ships seen fighting near it (like the FS2 cover art)" or a "fleet movement" where you get to see several capital ships moving in formation, essentially having the enemies "clash" in the middle. Think of medieval armies, with both sides charging each other, and in the center of it you have the fighting.
If however you want to retain the original concept of the pic, I suggest you take a look at some of Dark's art in the Image Galleries, he's got some awesome pics of this sort.
Hope that helps. Tha background really cool]
edit: the explosion are good, keep them. As well, it may just be my monitor, since it tends to show things as overyl dark, but most of the ships are just black silouttes. You should work on the lighting of the ships, make them lighter to shows of their details. If you could get the explosions to cast light onto the ships, that would looks really nice.