There are many ways..
Get a girlfriend best if its in your school and class, then make an
effort to study together. Work together, and archieve good results
and celebrate together! Of course, don't spend too much of a time
in relationship, rather you can ask her out everyday to study, and
on weekends go spend some time.
Another way is study something your interested in.. Find out what's
your best subject/interest, and hook up a study habbit..
For me, i wasn't interested in studying as well.. I hated A.Maths,
until i practice and practice.. and i fell in love with it.. It's
so terraffic to see yourselves improved remarkably and praised by
teachers, also very touching to see yourselves solving problems and
feeling a sense of archievement..