how to prepare CMAT upcoming exam??

Arshiya, Please check CMAT syllabus at:https://bschool.careers360.com/articles/cmat-syllabus . With 45 days for CMAT, you need to remember that you do not have time on your side. So you need to :

Manage time as efficiently as possible. You do not have time for distractions of whatsoever nature.

Believe in yourself that you can do it.

Practise a lot and revise equally.

Attempt as many mock tests as you can.

In the examination hall, read the question twice because there are chances of misreading a question.

Spend as much as 2-3 hours on Current affairs as this is an important section

Tips for QTDI:
QA can be categorised into Arithmetic, Algebra, Geometry and Advanced Mathematics. Practise chapter by chapter and develop mental calculations. Like practise more of basic summation, subtraction, fractions and tables. Numbers, Percentage, Profit and Loss, Simple and Compound Interest, Ratio, Proportionality, Time-Distance, Time-Work, Mixtures, Averages, Partnership, Permutation and Combinations, Probability, Set Theory, Progression and Series, Line, Angles, Triangles, Quadrilaterals, Polygon, Circles, Ares, Volume, Height and Distance, Coordinate Geometry, Basic Trigonometry are few important topics. Because this section involves mathematics and takes most of your time, your focus should be on solving the problems efficiently in the beginning. Even if it takes time, practise upto perfection. Practise as many questions as you can in the conventional way. As and when you get a grip on the subject, you can go for short cuts. Memorise tables, square roots, cube roots, conversion from percent to fraction, etc. Solve sample papers on Mathematics. In the beginning, do not worry about the time it takes. As you practise, you will get the hang of the subject and it will be easier for you.
Logical Reasoning:
Data Interpretation and Logical Reasoning needs to be practised as much as possible. Comparison of data, Data Analysis, taking clues, interpreting missing data, coming to conclusions and making future projections will be covered under this Category. The questions here are interlinked and so if you get one formula correct, cracking the next few questions will be easy. So it's important to memorise and practise formulae. You should cover topics like Data tables, Data Charts, Bar Diagrams, Pie Charts, Graphs, Data Comparison and Analysis. Solve as many sample papers as possible to get the hang of the section. Make notes when required. Regular practise can help you understand and solve the questions easily as time goes on.
Language Comprehension:
The ultimate key to improve your verbal ability is to read extensively and to read books from different genres. This ensures that when the time for reading comprehension comes you are well acquainted with different writing styles and topics. Reading extensively also improves your reading speeding over a period of time. There are no shortcuts here.