Can someone please tell me how to get these grades up?

Math: 89.1 (B+)
Language Arts: 93.1 (A-)
Gym: 81.3 (B-)
Chorus: 77.6 (C+)
Science: 90 (A)
Tech-Ed: 87 (B)
American History: 82 (B)
Reading: 85 (B)

Im trying to get straight A's this year :( but im doing sooo bad :((( Im in 8th grade ! PLEASEEE help .-. and MAYBE get a free tutor ?(: ;X haah <3 js x) ok ty