As I age, I find that softer matte color eye shadows are more flattering to my eyes. Dark shades can be too harsh and add years to my face. I try to stay in the same color family of my eyes to accent my eye color.
If you have brown eyes you've got it easy. I'm jealous; any color looks good on you. Don't be afraid to experiment with all colors. You'll find what appeals to you and flatters you the most. If you get stuck try charcoal, pewter, expresso, golden brown, mahogany, coppery bronze, dark purple, rich blue or deep greens.
Because I have droopy eye lids, my shadows used to crease or wear off by the end of the day. I learned to start with a clean, dry eye lid. Which means I'm removing any moisturizer that might have gotten on my eye lids. Since I've been using SeneGence eye shadows which are long lasting, I haven't had that problem. My shadow stays on all day and doesn't crease into the folds of my eyelids. Yahoo!!!!!