Alright, I'll offer some constructive criticism
Note that all these things I'm about to point out are not gospel, just my opinion. The points here are open to criticism themselves, as they always should be.
Your federation trainer is solid as it is for all the reasons I'm going to point out below. Take it as a good example on what I'm talking about.
Detail contrast is all about guiding the eye - making a person catch significant and nuanced details without being overwhelmed by them. Too much detail and things get noisy, too much empty space and it feels blank and unfinished. I've always found it helpful to break detailing down into three shape "Categories": Primary, Secondary, Tertiary.
Take a look at this, and if you'd like me to expand on it, let me know:
http://www.neilblevins.com/cg_education/primary_secondary_and_tertiary_shapes/primary_secondary_and_tertiary_shapes.htmExamples as to what could use some secondary and tertiary detailing.
Spruce up the underside of body of that guy and give us a bit more tertiary detailing on the wings :3
Tile patterns are a fine base, but to pull a texture together it needs more, something to make the repeating nature of the pattern not obvious, something to break up the monotony.
THIS has some great secondary shape-detail: the blue bits, the various shapes dotted around. all it needs is some fiddly tertiary bits
.
Color wise, I feel like your red is a bit too saturated.
Take a look at these as an on-the-cuff reference point.
http://kuler.adobe.com/#themeID/1765390http://kuler.adobe.com/#themeID/1778849http://kuler.adobe.com/#themeID/1763961