If you have a mirror available, freestyle while looking at yourself.
It’s better if others are also looking at you while you do this. The ideal situation is a full-length, full-wall mirror, like they have in dance studios. Your visual appearance makes a big impression on your freestyle performance. Your look, clothes, body language, dance moves, facial expression, smile, your eye focus — all these make a big impression and can communicate as much information as your words and flow. So take this opportunity to pay attention. If you look boring, think about how you can make yourself more dynamic. Try out different physical personas. Look at your reflection and engage with it as if it’s another person, and freestyle about what you see. You’re probably your own worst critic, so don’t be too brutal with your own reflection. You two have to go home together!