Be careful!
It is normal to use irony about yourself and to or about your good friends. However, if you use it to or about someone that you don’t know or don't have a good relationship with it might sound more like sarcasm. Sarcasm is irony that is bitter, cruel, or hurtful. Read this definition. And this one:

Sarcasm 1
Imagine you’re at a very busy restaurant. The server finally comes to your table and asks, “Can I take your order?”

Listen to this exchange.
Talk about it
- Does the server sound friendly?
- Does the customer sound friendly?
Check your answers
Does the server sound friendly?
Does the customer sound friendly?
Sarcasm 2
Look at this. What has happened? Is the response sincere, ironic, or sarcastic?

Sincere, ironic, or sarcastic?
Listen to these responses and talk about it: Does it sound sincere, ironic, or sarcastic?
1
2
3
Which sounds sincere?
Which sounds ironic?
Which sounds sarcastic?