Really the only way to get them, if you dont naturally have that shape is to make a THIN line, (if you want a more natural look, thicker for more dramatic) on the upper lid, and wing it out at the end, SIGHTLY beyond the end of the eye.
Or if you didnt want to do anything with eyeliner, you could take some light/ clear/brown mascara and put it on the upper lashes, emphasizing the outer corners of the eye, so it creates a slightly more accuntualted corner giving a cat eye effect
Hope this helps