As a student with dyscalculia, I always had difficulties with math.
But since I've taken a scientific high school, has been important to me to find a bulletproof way to study this subject.
I've thought that it would be interesting to share it with you, so there is a guide about studying math, maybe not in an easier way, but surely in a more effective one.
In class
Pay attention to the lesson. Taking notes will help you keep concentrated. Also keep an eye on examples and don't hesitate to ask someone to explain it.
Sometimes teachers asks for a volunteer in order to show the class how do exercises: don't be afraid and offer to do it, so the teacher will understand if you have understand the lesson and will not wait until test for give you a help.
After class
Study each time is an always valid advice, but in math this applies even more. In this way you can better define notions and have more time for exercise on different categories of math problems.
Always take some time for study the theory part from your textbook and notes. Try to have more exercise as possible. At least do assigned homeworks and ask for help when you don't know how to resolve one.
Often textbooks have guide exercises that show how to resolve them, be sure you don't skip them.
Before a test
Some days before a test, try to do more exercises than usual.
The 75%of times it isn't very useful, but it can help you feeling more prepared. So if you don't have time for it, don't worry and don't feel guilty.
If you haven't studied and exercised in a while, trying to catch up all at once will not help. I'm saying this for experience.
General advices
ask for a help from your friends: that's what friends are for!
Consider to take private lessons. Yes, they're expensive, but if you have many shortcomings, they can be the only solution. Personally, I've taken a lot of private lessons and they didn't help me very much. But many of my friends found them useful. So try if you can.
A teacher with an interested class is an happy teacher. Don't be afraid to mess up and remember that there are no "stupid questions"
Never despair. There is always time to improve. Math is that kind of subject that has to be appreciated, otherwise became difficult to find the right motivation to study it.
I hope that you will find this "masterpost" useful, so if you have any questions or think that I've missed something, please send me an ask/message.
Wish you all the best of luck for school!