I know, I know school sucks !! so here are some tips that will hopefully make it better.

SLEEP
I know you probably heard this a thousand times but it will seriously help you stay concentrated in class if you are fully rested.

EAT
If you are HUNGRY you are not going to be concentrating on your Homework / Test and you will definitely not listen to your teacher because you will be thinking of food and hearing your stomach.

PAY ATTENTION
If you actually listen to your teacher you will be better equipped with doing your homework which brings me to #4

TAKE NOTES
when you take notes you can look back at what your teacher said and what you were confused about and then you will be better equipped at doing the homework or taking the test.

TAKE BREAKS
when you are studying taking breaks is a good idea to keep you motivated but make sure you go back to studying after.

STUDY WITH A FRIEND
it is a good idea to have someone else there to motivate you to study and you can quiz each other. just make sure you don't get caught up in something that is not homework.

CHECK YOUR TEST
Make sure you check your test before you hand it in just in case you forgot something. you definitely don't want to forget to answer that question you skipped because you didn't know it at the time.

MOST IMPORTANTLY try and have FUN or at least sort of enjoyable where comfy clothes, have food and drinks nearby, and when your grades go up or you get a good grade on that test that was just really hard reward yourself.