Some Study Techniques That Helped Myself Succeed in High School:
Set Goals for Yourself: Growing up I always looked up to my older brother who excelled in school. I wanted to be just like him which caused me to work harder in class.
Take Breaks: Homework can be overwhelming at times especially after long days of school. Make sure you split up your work into smaller sections and take breaks to prevent yourself from burning out.
Spend More Time on Subjects You Struggle With: Personally I excel in math, but tend to struggle sometimes with English. Rather than splitting my time evenly between the two, I focus more on English.
Use Audiobooks: Whenever you have to read a book for class I highly recommend the use of Audible. Listening to someone else read the story and following along with a hardcopy was very helpful for myself.
Seek Out Your Teachers for Help: If you are struggling to understand a concept in class, see your teacher after school. More often than not they will explain the material to you until you comprehend it.
Budget Your Time: If you know you have a large project coming up, do not wait until the night before it is due to complete it. Space it out over time.