value: measure of relative lightness to darkness.
Consider having a full color pallet of eyeshadow on hand and leave at home to prevent breakage. another one which I like is the eyeshadow in color wheel setup. Pretty helpful for starter playing around with shadow. Usually complimentary color work nice together for eyeshadow that wanted to pop-out. For a more subtle look is the closer one on both side.
(first image at oocosmetic.blogspot.com and second at redgingercosmetic.com)