How do I reinvent myself for 8th grade year?

My 7th grade year wasn't really good, it was really depressing. I've always been a shy, quiet, insecure person. I'm not a nerd, geek, or dork, but I'm not exactly that popular everyone-likes-me-and-wants-to-be-like-j… type of person either. The closest I've come to anything with a girl was when one kissed me on the cheek cause her friends said she wouldn't. For my 8th grade year, I want to reinvent myself almost completely. I want to be more confident, secure, and outgoing. I want to be more liked by people, I want to be cooler. Have a better body, be more athletic (in gym this year, I sucked at almost every sport we did, especially basketball, plus I don't know a lot about the sport either, but I want to, football too). I have a whole summer to try to be more like this, so tell me, what can I do this summer to go to 8th grade and be an all-around better and cooler student.