Remember something that makes us happy. If we (humans) are in a funk thinking back to a happy time could give us enough energy to move forward with our day.
Smile like we just got everything we wanted. This is similar to fake it until we make it. It's okay to be happy before we are actually happy. Imagine ourselves getting something that we want may help us get in the mood to get what we want.
Go outside; especially to Nature. Nature has an a healing property that seems necessary to life. Nature allows us to slow down and feel comfortable enough to be in the moment. What does being in the moment do? It helps us pay attention to become more aware.