Highschool Freshman advice?

[Krysta]

I start school August 14 and it's a full school day.
I've been told the friends you walk into highschool won't be the same half way through it, is it true?
My grades were really bad in 8th grade and advice how to keep them up?
As for sports and clubs there is a couple clubs that I'm going to join.
As for orientation my school is weird and we had that in March, they just went over class descriptions and stuff we didn't get are schedules.
Then in May we toured the school.

Main thing I want advice on is:
How to keep your grades up?
Is Freshman Friday true?
Advice in how NOT to get lost the First day?
Bringing your lunch the first day?
Any other tips for highschool?
*10 points best answer*