Acting cool is all about projecting confidence and a relaxed attitude. Here are some tips on how to act cool:

1. Dress well: Dress in a way that makes you feel confident and comfortable. Find your own personal style and wear clothes that fit well.

2. Practice good posture: Stand up straight with your shoulders back and head held high. Good posture makes you look more confident and in control.

3. Speak calmly and clearly: When you speak, try to project a calm and confident tone. Speak clearly and avoid mumbling or speaking too quickly.

4. Be a good listener: Cool people listen more than they talk. When someone else is speaking, listen attentively and ask questions to show you're interested.

5. Use humor: Use humor to lighten the mood and make others feel comfortable around you. But avoid being too sarcastic or making jokes at others' expense.

6. Stay calm under pressure: When faced with a stressful situation, take a deep breath and stay calm. Cool people don't panic or overreact.

7. Be authentic: Don't try to be someone you're not. Being true to yourself is the ultimate cool.

Remember that acting cool is not about trying to impress others, but rather about being comfortable in your own skin and projecting confidence.