You can practice any emotion by controlling your body.
When you put yourself in a happier position, your mood can be boosted. But the same effect can happen with “unhappy” actions. If you start to practice a depressed face, you’ll notice how your mood is getting worse. You can try it even without a pencil.
As far as other simple actions that can make you happier, psychologists recommend standing tall and breathing well so that you feel more confident.