Clown on uUnicycle Clown on Unicycle

In English words in titles (all but particles and articles) usually get capitalised.

Clown onThe clown is on a unicycle. The clown is on a unicycle.

If you are wanting to practice writing using creative/prose/poetic English you can keep what you have. If you want it to be correct grammatically and formal please see the correction.

HA happy clown is performing on single-wheel bicycle, doing balances with a water jaa unicycle, balancing a jug of water on his head. A happy clown is performing on a unicycle, balancing a jug of water on his head.

HThe happy clown performs on a single-wheeled bicycle, doing balances with a water jar on his head. The happy clown performs on a single-wheeled bicycle, doing balances with a water jar on his head.

The jar hasre are some a cute flowers inside the jug. There are some cute flowers inside the jug.

Without having seen the image I can't say if "cute" is inappropriate here, but "pretty" would be more common.

The jar has some a cute flowers inside. The jar has some cute flowers inside.

He is glad to entertain to all people, children and adults, with his balanceing acts. He is glad to entertain all people, children and adults, with his balancing acts.

He is glad to entertain to all of the people, both children and adults, with his balances. He is glad to entertain all of the people, both children and adults, with his balances.

This illustration can put a touch of joy in your lifves. This illustration can put a touch of joy in your lives.

This illustration can put a touch of joy in your lifes. This illustration can put a touch of joy in your life.

Additional correction "This image of the clown can put a touch of joy in your life" or "This illustration puts a touch of joy in their lives." (the 2nd option if you are describing a picture and continuing to discuss the people looking at the clown)