Assalamu Alaikum
u can set urself to a goal,
like for me, im trying my best to get good grades so that i can get into the university of my choice and inshallah so that i may have time to do other things that i dont have time to do
i mean u can like reward urself and punish urself to help u concentrate...and always make dua so that Allah can help u along the way inshallah.
although for me, i can only concentrate when no one is around and all noise is absent. basically when im alone with no interruptions, but at school i cant concentrate at all cuz ppl around me are noisy and stuff or i just feel too tired, but if i must do the work than i must do the work because my future is what drives me. knowing that what i do now will affect my future, compells me to study and concentrate
fi aman Allah
w'salaam