Take Good Care of Yourself
Firstly, it's important you take good care of yourself. It's much easier to be positive when you are eating well, exercising, getting enough rest and dressing well.

Detach From Negative Thoughts
Most of us are guilty of this and we ended up not getting things done.
Positive thought only, your thoughts can't hold any power over you if you don't judge them. If you notice yourself having a negative thought, detach from it, witness it, and don't follow it.

Increase Your Social Activity
By increasing social activity, you decrease loneliness. Surround yourself with healthy, happy people, and their positive energy will affect you in a positive way!

Volunteer for an Organization, or Help Another Person
Everyone feels good after helping. You can volunteer your time, your money, or your resources. The more positive energy you put out into the world, the more you will receive in return.

Remind Yourself of the Things You Are Grateful For
Stresses and challenges will arise every now and then, take 60 seconds to remind yourself of the thing you've done right in your life and appreciate them, this will make a huge difference and keep you going.