The act of smiling itself helps you feel better. Also, keep in mind that your facial muscles need time to rest and recover too, so don't overuse them by frowning or scowling constantly. It's important to find a happy medium between too much smiling and not enough smiling - it's all about balance. Finally, if you want to look happier still, then work on improving your mood. Feeling bad about yourself or the world around you will just pass across your face, so start thinking positively and feeling grateful for what you do have.