I’m glad you are on the right mindset to working hard! :) That’s always a good start! 
My parents raised me to strive for A’s in school and to work my hardest. At first, I did it just to avoid being lectured at, but now, it’s just how I am. I just feel the need to work hard for them, so I can give them a better life in the long run, somewhat like repaying them for all they’ve done for me.  I want them to retire early and just have fun. They’ve worked so hard to get me here today.

So through them, I found my motivation. When I get lazy in school (and trust me, this happens).. I always think about them,  and my little sisters. I think about how my success in school has motivated my younger sisters to work hard also. I think about when my little sister Erica said she’d work hard to get straight A’s so she can get more full ride scholarships than me. LOL. Those little memories were driving forces that pushed me through the sleepless nights studying for exams and what not. 

And lastly, it’s just important that you are also doing this for you. You’ll realize this soon enough. Once you find out what you want to do in life, and why you want to study. Find your motivation, and the studying gets easier. 

I also have a few study tips:

- start early, make a schedule and space things out. It’s better to study little by little and review each day, than to cram (your exam grades will definitely improve!)

- use a planner, I can’t live without mine. It keeps me on track and organized. 

- taking good notes is definitely essential, if you are a slow note taker, bring a recording device. I always take my notes on my laptop, because I’m a freak typer and get every single word down. After the lecture, I go over my notes and rewatch/listen to the lecture and highlight the key things that the professor said. This will get easier as you get more and more comfortable with their teaching style. With those notes, you can make a study guide - I always shorten it as much as possible and make it as easy to understand as possible. I would print out those notes, and then study off of them, as I go, I tend to add little notes or drawings to help me remember them better. Whatever works for you

If you are still in high school, now is the perfect time to explore what time you study best, day or night. I study best at night (after I’ve eaten lol) You need to explore how you study best, with or without music, where, etc. ;) 

I hope this helps, and I wish you all the best!