ah glad that you like the designs!
I've answered this before with a few examples :]

It's a bit hard to explain because I rarely plan ahead a character design, it's usually entirely random
sometimes the most creative and unique designs come from spontaneous inspiration

generally, I first draw the base of the character, and then add the details as I go
start with basic shapes, and fill in the details

as for patterns, I would start by adding the base color and draw a quick guide where the patterns will go, then, I would fill in the details on top of the guide
I try to build up the patterns from light to dark, or vice versa

I sometimes struggle to come up with a color palette, I'd usually pick the colors randomly and hope that it looks somewhat appealing
I try to keep each color on a different layer, just in case I need to make some adjustments or change the overall palette
but I do use layer modes a lot (eg. Exclude, Difference, Overlay) to make minor adjustments or come up with a complete different palette!

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I hope that helps give you a little more insight!