I wanted to make an emblem for my self and this is pretty much first version i came up with. It still feels like it needs something but it's a start. Also this was inspired by these things: warhammer40k.wikia.com/wiki/Im…
I've dabbled a little in heraldry, so forgive me for inserting my inexpert opinion.
There's nothing against putting charges (symbols like the crowns and the moth) on top of a party per cross (splitting the shield up into quarters with a vertical and a horizontal line) but it does run up against the tincture rule: colors (in this case, black and red) should not be put on top of or adjacent to other colors but should instead be next to metals (white and gold). That rule is mostly there for the purpose of contrast, so it can be broken (depending on whom one asks) if contrast remains.
Your choice of field (especially the "chequy" checkerboard part; a quick Google image search shows that it's hard to put charges on) makes it hard to put a charge right on top of it. One possibility, to keep the fields, would be to move the charges to the red fields, like the little shield I've doodled on the left below. Another option is to add a "escutchion"--a smaller shield shape--to the middle of some color you can cheat with (black on blue is usually considered acceptable). A third choice could be to add a thick white border or fimbriation around the moth to increase contrast.
This is of course moot if heraldric rules need not apply, but hey.