My best friend

Today, I am going introduce my best friend to all of you.
As everyone knows, friends are very important. Although I have lots of friends, but Aurial is my best friend. She is a very optimistic girl, and always cheerful. When I didn’t do well on an exam, I would feel very down. She'd always encourage me and try to cheer me up. She'd tell me why I didn’t do well and how do better. I feel very grateful for her help.
She is a very energetic girl. She loves sports. Unlike other teens, she dislikes watching TV and computer games. In her words, they are "useless and boring." Because of her, I've also become much more creative. We climb mountains together and enjoy the beauty of the nature. We go to the beach together and feel the coolness of the water.
So she is my best friend Aurial. A lovely, passionate girl!

Good job! Keep in mind English pronunciation rules (aka the correct use of periods and commas). Avoid run-on sentences at all costs.

Also, if you use "would" to describe a habitual, past action make sure every verb uses the same structure. Parallelism is best.

Keep on writing and reading! If you have any questions about my corrections, please feel free to ask me.