Pretty much all you have to do is create a sylesti that has two colors. It has to either have the same two colors as the sylesti above it, just a different kind of sylesti, or it can be the same sylesti with one of the colors changed. you can only have two colors, but the shades of each color can vary, as long as it is still recognizable as that color. Traits don't matter, nor does gender.
I know I stink at explaining things, so here is an example:
Say the person above you made this sylesti:
Green and brown Nytekrie

You could post either something like this:
Yellow and brown Nytekrie

Or this: Green and brown Faelora
Hopefully it makes at least a little sense now.
Here's the first sylesti :
Blue and grey Griffi:

Blue/Grey Nytekrie

Like this?

Purple/Grey Qitari (changed a color)

(totally reminds me of Uno, lol)

Purple & Grey Ryori

Purple/Grey Sylvorpa.

Purple and Blue sylvorpa

Purple and blue Aurleon:

Purple and Blue Kelpari