D’Addario suggests keeping track of the good things in your life by recording them in a journal each night, writing down five to 10 things for which you’re grateful—small or large—and that happened during the day. She says recognising, acknowledging, and appreciating what you feel grateful for can reduce depression and stress, and increase your overall optimism and wellbeing.

If you’re not into journaling, then Miller suggest simply thinking or talking about what went right during the day. “If you eat dinner with family at night, make it a habit to only talk about what you enjoyed that day,” she suggests, and adds that hearing about others’ experiences can make you a more positive person, too.

Everyone has negative thoughts—even the most optimistic people. But what you do when those negative thoughts enter your mind is what really matters, says Miller. She recommends tracking when your mind tends to focus on negative things or replays difficult situations, then actively re-directing those thoughts to more positive ideas. “Give yourself a few positive go-to thoughts, and work on directing your brain to those if you notice anything negative creep in,” she says. “This practice will help your mind to automatically go towards more positive thinking on its own. And hopefully, it will lead to less worry—and less tossing and turning—when it's time to sleep.”