How to be outgoing

Hello, I'm going into high school this upcoming fall and I read some posts on hear that say to be outgoing. I'm a somewhat extroverted person but also introverted. I don't know how to explain it. In 7th grade I was a popular kid but im going to different high school and was wondering how to be outgoing and still be somewhat comfortable. I know thats prob not possible but yeah. I homeschooled for 8th btw. I'm getting kinda scared for high school as I gets closer. I've always been very shy so thats the reason of this post.