Do not think
It is surprising indeed that you if you fail Calculus you fail because you think too much. Most probably you are distracted by questions:
Why I need math?
Where math is used?
How math discoveries were made?
When math discoveries were made?
How to apply math?
And so on...
If you thame your mind and learn to not think about this questions you will deal with math
Regrets and fear of future
Sometimes the Devil will play another game.
You see we all have regrets and grievences. There is not a single person on earth who doesnt have some kind of resentment. And Devil will bring this moment before your eyes, throwing your mind to re live this moment. Please dont fall for his game. Not because you are not important. Because resentment doesnt provide you benefits. It doesnt have positive value. So whenever you feel resentment STOP! Dont waste your time. Stop yourself and focus on math, resentment will not teach you math. But if you read or do exercises it will teach you math.
The same goes for the fear of Future. It is the same trick but from the other side. There is no value in fearing your exam and not sleeping before exam. Please be aware that is the Devil who plays this trick and he doesnt want you to shine all your talents.
Know what you know
Socrates said that he knows what he doesnt know. And many of us dont know what we dont know. Thats very important trick. You probably read something, and think that once you read something you already know this. No. Math is not literature. The only way to download mathematical knowledge in to your mind is exercises. The only way to build new mathematical neural network in to your brain is exercises. Please do exercises.
That is it
That is all you need to master math. With this three tricks Devil defits you. Dont be fool. Dont fall for this tricks.