Positive messages that you can see on your desktop or phone every day can provide a daily reminder/ encouragement.
Mine is very simply: "I can do it."
Being thankful and writing down three things that you are thankful for everyday can change pessimism to optimism.
Lastly, surrounding yourself with positive people is crucial. I like to find friends who are kind and welcoming others. It lets me know that they care about more than just themselves, and are willing to be supporting of me and all my pursuits. Loyal and kindhearted friends are the best daily reminders to keep a positive outlook.
.... literally you can't go for ten minutes with my friends without them stating something that is good about the day!