I found that making sure my underthings, especially bras, fit well, makes me look a lot better. I stay away from too much baggy black clothing. If I know I'm going to have my picture taken, I make my makeup a little more dramatic. Otherwise, just getting the right haircut and taking care of your skin are key to not looking worn-out. I also try to make sure my eyebrows are groomed and penciled in a little. Also, blush, blush, blush. I love blush. SUBTLE and soft blush. It makes you look pretty even if the rest of you isn't put together.
Feeling ugly, but I don't like makeup. I look horrible in photos.....HELP! - Page 2
You buy a kit (there available in pharmacies where I live, but maybe not everywhere? You can order online too..), then follow the instructions. Basically you get a little bowl, mix two liquids together, apply to your eyelashes & brows with the wand (like you would with mascara), leave it ten minutes, then rinse it off very thoroughly. Try not to get it in your eyes because it stings!
If you're fair-haired and doing your eyebrows then I strongly recommend you leave the dye on for just 3-5 minutes to start with, so that they don't end up too dark. You can always do it again if you want them darker.
Hope that helps! It's a little intimidating the first time you do it, but super easy after a couple of tries. :)