The lighting of the ships and planet doesn't fit the background - as said before, use similar colours for ships and background.
Also, centered text would probably look better, as you present the names in the middle of the sig.
As well, you might want to use similar styles for the fonts, not a blue border for the rank and white with texture for the title...
My example of how it could be done; try to keep theme as clean as possible. Think about using brushes, and keep your color scheme as minimal as possible (here, mostly black, white, grey and a hint of red lighting and order brown on metallic surface)
Also note the pattern on which I positioned the fighters so they seem to fly in formation instead of just being pasted in the picture for show. And them being an important theme, they are not obstructed by anything.
That looks good Yue Fei,maybe that ships should be a bit bigger,but you made your point.It's looks cool.
BirdTalon,you have good ideas,but I think that Order members need more serious signature.Don't get me wrong your idea is good,but it reminds me to much on nomads systems (purple background) and those white letters doesn't fits me good.
That's my opinion.
My signature is made by one of Order member Ophidian and it's example how would Order sig had to look like,at least for me,well everyone has their wishes and tastes..Simple and not much colors.
I hope there is no bad feelings:)