Mathematics is a kind of subjects which demand practice. It's not like other subjects,you read and you will understand. The concept will be clear when you practice questions. Some of the things ,you can follow are.

. Understand the syllabus -  The first and basic step is to understand the syllabus of subject . Then understand the core concepts of the subject that would be useful throughout the subject.

. Understand the concept - do not just try to remember the formulas and theorem. Instead, try to understand the concept behind them.

. Make a study plan - A proper study plan will help you manage the things in a strategic way . Understand the topics which are easy for you and the topics you find difficulty in solving. Then accordingly give time to topics.

Practice - practice is th key to master mathematics. The more you practice, the more you become better at subject.

Attempt previous year question - try to solve various previous year question papers, that will help you analyse your weak topics. And then you can also analyse topics of high and low weightage and accordingly focus on topics.