I just submitted my avatar, too. >u< This is only my third time in the arena, although I think the first time doesn't count, since the first time I accidentally submitted my avatar to the wrong arena, haha.
The second time I submitted my own take on a human version of the Rat King from the Nutcracker Ballet to the Original Avatar Arena. And this time, I'm a young fairy princess, for lack of a better idea for a name, considering I have wings, a crown, and a wand, haha.
As far as themes go, I don't really have any specific themes since this is only my third (technically only second) time submitting. But when it comes to making avatars, usually I center the avatar around one or two items and work from there.
I like things to be color coordinated and to look like they could be a character from a book or something, haha. It's usually avatars that are fantasy or sci fi inspired or that look like they're from a past time in history.
As for what I dislike, I mostly just dislike really cluttered avatars, although I'm sure I've been guilty of making avatars that have seem cluttered to other people from time to time.
As far as trends, I actually do very much like the different body mods, such as leg and arm mods, whether they look like normal legs and arms or the legs and arms of fantasy creatures. It's just fun to have the option of posing avatars differently, regardless. And like
said, it helps with cross-dressing a bit, which is always fun, haha.