how I can prepare for mat entrance examinations

First go through the entire syllabus and then make a proper and programmatic study schedule. There will be questions asked from these topics- English Language, Basic Mathematics, Intelligence and Critical Reasoning, Data Analysis and Sufficiency and Indian And Global Environment. http://bschool.careers360.com/articles/mat-syllabus
Choosing books sectionwise would be better. For English Language and Comprehension part, Word Power Made easy by Norman Lewis, English Grammar by Wren and Martin. For Indian and Global Environment, you can prepare from Manorama Year Book. Study Package for MAT by Arun Sharma. For Mathematics part, practice from How to Prepare for Quantitative Aptitude for CAT by Arun Sharma. How to Prepare for Data Interpretation for CAT by Arun Sharma for Data Analysis. Once done with the syllabus, you can move on to solving previous year test papers and give mock tests as much as possible. We have free Mock test for MAT http://learn.careers360.com/test-series-mat-free-mock-test/