I have been making many friends since I was a kid, but now there are only a few friends I keep in contact with. I will observe whether or not a person is suitable for me when we hang out. I will ask myself some questions like "Does he/she have the same hobbies as me?" or "Is his/her value system the same as me?". If we have so many things in common, we would get along better. And I think the most important sign to tell someone whether they are a true friend or not, is to see if they will give a hand when you need help. The true friend will always help you and give you good advice.