Try changing things randomly and observe closely what it makes you feel.
Start eating soup with a fork.
Always return home by a different path, no matter how long it takes.
Strike up conversations with random people anywhere, anytime.
Look at familiar things with new eyes.
Learn to understand a piece of music you don't like.
Try telling nothing but the truth one day and nothing but lies the other. If anyone asks, tell them you are conducting an experiment your psychologist suggested. Having a psychologist is fashionable.
Leave your comfort zone. If you don't know where it is, find your comfort zone. Then leave it.
Do one thing every day that frightens you.
Make up some other experiments not in this list and do them.