Here are some of the books name you can prefer for english.

Firsly prefer Wren and Martin for the basic level

then prefer Objective general English by S P Bakshi, Mirror of Common Error

Advance English Grammer by Martin Hewings
Quick Learning Onjective General English by R S aggrawal

I would also suggest you to read newspapers like The Hindu, Magazines.

Here are some preparation tips you can follow.

To prepare for These Exams -

• Try to solve Previous Year Question Papers & Mock Test Papers.
• It will give you an idea about Exam pattern & it will make your speed faster of solving questions.
• Try to increase the level of difficulty of the questions you solve.
• It is really important to make your speed faster. Because you have to solve at least 160 questions out of 200.
• Focus on the topics on which you are not good.
• In Reasoning & Quantitative Aptitude, there are some topics, which can be solved by short tricks, learn those tricks to solve questions quickly.
• Don’t waste time on one question, if any question is takes more time, leave it for last.

Good Luck!