Kerr says many successful people take the time just before bed to reflect on, or to write down, three things they are appreciative of that happened that day. 

"Keeping a 'gratitude journal' also reminds people of the progress they made that day in any aspect of their life, which in turn serves as a key way to stay motivated, especially when going through a challenging period."

It's easy to fall into the trap of replaying negative situations from the day that you wish you had handled differently. Regardless of how badly the day went, successful people typically manage to avoid that pessimistic spiral of negative self-talk because they know it will only create more stress.

Benjamin Franklin famously asked himself the same self-improvement question every night: "What good have I done today?"

"Remember to take some time to reflect on the positive moments of the day and celebrate the successes, even if they were few and far between," Woodward says.

Vanderkam adds: "Taking a few moments to think about what went right over the course of the day can put you in a positive, grateful mood."