Look, when I was in high school a yr back I used to suck at maths. But really the way I studied was the one holding me back. Before going into details, please take pieces of advice from me. Most importantly have confidence. Seriously this is really helpful. Anywhere you go people with confidence have that 'I Can Do This' vibe, trust me on that. I mean if they can do it why can't u. Second, its never too late to do anything. Here are some tips: *Know your productive-time-range, what works for you best. For eg I am super productive from 1:00 p.m.-5:00p.m. local time. Discover ur time and during those time avoid any means of distraction. *Air plane mode! That's a must. Plus as you sit to study put everything u need on the desk ur studying; water, pen, pencil, paper(super important), earphone, ex book, text book, reference book....etc so u can avoid standing up. Choose to read in a quiet place and get ur ass off of your bed. Bed is a really bad idea: what u need to know is that ur brain has adjusted itself to think bed is a place to sleep, not reading. So use that for ur advantage: read at a specific place...so everytime u sit there ur brain gets ready to read. *Use different methods: POMODORO METHOD(Google it.. Its so effective),study in a 2-3 groups(not more) where everyone gets to have a topic and describe it, When reading make it fun, use a song mnemonics...make a funny drama in ur head...do what helps. *Take in-between breaks. Sitting straight for 4 hrs won't help...take breaks and refresh ur self...not long breaks tho. *Use ur parents as motivation...to make them proud or ur ambition. Don't forget to pray too. I wish you the best fellow.