Whenever i have tried making tiny patterns, like 10 x 10 pixels, only things that i have ever been able to make look good is only diagonal lines. Other than that i have no idea. I suppose it has go to do something with painting principles like how we perceive tiny light and shadow (up/down,inside/outside). I hope made this question clear enough.
Looks good is a very subjective description...
I like to make connecting lines so the end result looks woven. I also keep keep colors to a minimum, typically just 2 or 3.
Why don't you start by collecting a few samples that you like, then recreate them with a few small touches of your own?