/cgl/ - Cosplay & EGL

As said earlier, OP, otome is more about the feel of the outfit rather than the actual pieces. There aren't really concrete rules.
It's cute and feminine, with a sort of whimsical, fairytale feeling to it. Oftentimes, there are almost-clashing-but-not-quite colors, patterns, and motifs. Dresses and skirts are most popular, but pants and shorts can work. Peter pan collars, small hairbows, cute hats, low cute heels and boots, patterned socks and tights (yes, knit tights will very much work). Popular motifs are deer, flowers, fruit, lately cats (although these are popular all over Japan right now). Kind of kitschy prints.
Otome can overlap with a lot of styles, like lolita, himkaji (a style of gyaru), and twee (a style in the West).

This is my favorite otome tumblr:
http://fuckyeahotomekei.tumblr.com/
There's also this one:
http://otomemaiden.tumblr.com
And this one:
http://otomestyle.tumblr.com/

Check out the following brands for inspiration:
Emily Temple cute, Shirley Temple, Emily Temple Lulu (the above three are the same overarching company), Milk, Jane Marple, axes femme
Some brand tumblrs:
http://emilytemplecute.tumblr.com/
http://axesfemme.tumblr.com