Whenever I hear "double lid" I imagine a second eyelid which is like a one-way mirror; it appears your eyes are closed to others, but you can still see out them...
Anyhow, people think I am part Asian sometimes, and I have a deep eyelid crease.
I do thick, liquid liner a lot. I probably look better with just that than with eyeshadow. My favorite liner is mac liquidlast, and sometimes I'll put mac fluidline over it (a gel liner). I tend to wing it out & exaggerate the almond shape of my eyes. I think this is what gives me an Asian look to some.