1) Practise, Practise, Practise - as we know that practise makes a man perfect. So, practise is the key to success in maths. Maths needs a lot of practise. so ya it' very very very important.
2) Formula - Learning these is the most important thing after practise. As u are in 6th grade, so there will not as much formulas, and not difficult to remember.
3) regular studying - Maths need a lot of time and attention. If u don't want to panic near exams, Study daily and regularly.
4) Revision near exams - So, now u have practise a lot, remembered all the forms, studied regularly, now is the time for exams So now u have to revise back what u have learnt. Do revision.
5) Don't panic - As u mentioned above, u r in class 6th so u don't wanna panic if u r not getting anything. Just ask for help from someone elder and if not i am there u can take my help and also brainly is there for u.

plzzz..............mark it as brainliest if it helped u..........  :-)