So first of all, making friends is not about knowing before you start talking that you have the same interest, but when you get to know each other, seeing that you have some subjects which you both like. Always try to be interested in their well-being, ask how their tests went, how they are feeling.... etcetera etcetera...
I know it is hard for some people to start talking to a person they do not even know. I felt the same for a long time, but now I just take a deep breath, introduce myself and keep the conversation going. Some of those people are now really close friends to me.
So:
-Smile
-Be interested
-Don't think, just go and talk to new people everyday. Start with a girl/boy who is sitting next to you in class, or the person that you meet in a shop, or in the supermarket. Those people you don't know, are probably really nice people and there is nothing to be scared of.
-Keep the conversation going. Try to keep bringing up subjects, just don't let the conversation die. And you might say:"But I don't know what to say". That is not true, you are just thinking of things in your head, and disliking them, because you are afraid this person might judge you. But wait what: this is a random person you don't even know, so stop caring what they think!
-And the last advice is: You do not need many friends, you only need those who are real friends.
I hope this helped you, and if you have any questions you can always PM me :)