Friends are a great way to practice. They can give you critique. They will let you know whether the compliment was good or bad. They can help improve the compliment to even sound better. One never really gets better at anything until told what is wrong. When you are told what you are doing wrong, it is simple to improve it. If you are a girl, you should flirt with a guy friend? Why? Because he is a guy and guys know what they want to hear. If you are a guy, you should flirt with a girl friend? Why? Because of the same reason. Girls know what girls want to hear!