Treat yourself as if you were a friend to yourself. When you're feeling down on yourself, think about what advice you'd give a friend who was feeling down. Now try to put that advice into practice.
Optimism is partly inherited and partly learned. You can find your inner ray of sunshine even if you were born into a family of gloomy people.
Self-esteem is how you perceive yourself. When you find yourself criticising yourself, ask yourself, "Would I say that to my best friend?" You most likely would not. Instead, tell yourself something encouraging, like "You're a bright person."
Gratitude, among other things, can improve your mood. A recent two-part study, for example, discovered that practising gratitude can significantly boost feelings of hope and happiness.