How do I make new friends in the first year of High school? And leave the bad ones behind?

Well I've had the same friends since 6th grade. Now that next year will be my first year of high school I want to find some new friends. I've grown apart from my other friends. They're not like me anymore. I feel like I grew up. And they didn't. Some are so demanding and spoiled. But most of all, not many are good friends back. And I can;t talk to them seriously or ask them for advice. When they can do both with me.

But anyways I want to know ways to meet new people and how to start a friendship. And way not too embarissing and out there. Since I'm shy around new people, but after a while I'm very loud and outgoing.

I need new friends, and I don't want to keep these old friends that aren't well, good friends. And I think starting at a new school (not a new town or kids, just high school)

Any advice?