expand my social circle

So this is really hard for me.
How do I just go up to people, and like, talk?
I’m in 11th grade and school is basicly the best place to find some friends.
Help?

Okay so I just started school the other day. That’s my main source of finding new friends.

Psychology – I’ve got a bunch of aquaintences in that class, and I know since we all sit in a group, we’ll be able to get to know eachother more and become good friends.

English – Okay, so I used to have this close friend, but we haven’t really talked in 2 years, and now she’s in my class. We sit beside eachother but it’s akward because we haven’t seen eachother for so long. That’s the problem. I have to find a way to make it less akward so we can become good friends agian.

Cooking – I know no one in that class, since most of them are grade 12s. But since we have a lot of group work, I’m sure we’ll be able to get to know eachother and become friends.

Fashion – All my close friends are in that class. But there are a lot of new people there too, which I’m hoping to become closer to.

maybe after march break I’ll begin doing some actual work on this goal.
The only place for me to make friends right now is at school, unless I join something (dont know what..). Maybe in the summer I’ll go out in my neighborhood more, and get more friends there.. but right now, it’s school.
When I get to school, instead of meeting with the same four people I usually do, I’ll spend time with my other friends who arent very close to me anymore (used to be) and talk to them. And at lunch, I’ll go downstairs and see my other friends who I used to be close with and have lunch with them (one of them was always saying how we should hang out since we never see eachother, so it’s the perfect chance.)
I’ll also start to be more talkative in class. I’m usually just sitting there, bored because I’m tired, and never actually thought of talking much.

The problem isnt that I’m shy.
The problem is that I cant keep my friends close to me, so than we drift apart.
I blame highschool for this.
It’s because by the time I start getting close to the friends I’ve made in that class, it’s time for a new semester and then I barely see them agian. And when I do, I’m afraid to go up to them and talk to them because I think that maybe they dont want to talk to me.
And this is what makes me only stay with the same for people.
Everyone else is temporary friends.