My method of studying is to always pay attention in class. I always listen attentively to my teacher and then when I go home I'l revised what I learn for the day. I also find it helpful that I always play basketball early in the morning before I start my lesson . That keeps my mind alert and fresh so that I can pay more attention. During break / recess time I also spent 15 mins to play basketball to recharged my energy and mind . I do know of some people that swim before lesson as well. Basically it's important to listen during lesson and take notes. For certain subjects I actually don't really put much effort but since I listen I can easily pull it off without having to force myself too much. So it depends different people have different way. You can try do mind mapping as well. If possible try sit right infront of your teacher's table which I always do to prevent myself from slacking off or day dreaming. When you sit infront your teacher will tend to look at your work for references , see what you do and etc.. My teacher always ask me where did she stop the last lesson, lend my notes , and also ask me questions since I'm right infront of the whiteboard :) Set a goal and motivate yourself everyday that's what I do :)

honestly, it's just repetition. i have a terrible memory but if i look at stuff over and over again, i can remember it. also, eating something while studying kind of works for me. since i'm occupied with eating, i can't daydream AND eat AND study at the same time, and i can cut down on multitasking. it depends on the person, but sometimes dull background noise can help you study.
at school, you have to force yourself to pay attention. there's no shortcut to not getting distracted (unless you really like the topic, then you'll naturally be focused). i use the clock as my motivation to stay focused, that i only have twenty minutes, ten minutes, etc. left before i get to be free. maybe you're just bored and disinterested in what you're studying?

Taking notes..make it sophisticated..with highlighter..natural response: eyes like something catchy so you will not be bored reading your notes.

Take a rest when you are studying/review things at home..make yourself relax.

Review things with friends is also effective.. But some ppl prefer alone.

Sit at the front row..teachers tend to remember when they are grading you..most of the times it works to give you plus.

Stop taking your phone to school, sit right in front and say shut up to your friends when they try to talk with you and distract you.
Force yourself to take notes, don't let yourself daydream and if you do don't shrug it off like that's just what you expected. Change comes if you think the problem matters. Just try harder. Hard work always pays off. Succes with your exam