Sit, or lay down. Or you can do it while you go for a walk, whatever you prefer.
Breath slowly and in through your nose. Focus on your heart center, feel it expand, as you begin to think of all the things in your life you are grateful for; relationships, food, shelter, your ability to walk and breath, ect. Anything you can think of. You can even go further and feel grateful for things which haven't yet manifested in your life, but you wish for. Let the energy of love and gratitude grow and expand in your energy field.
It's a powerful way to quickly uplift and shift you to a higher frequency, and attract more good things into your life.