Well below I have given you some good books to prepare for the CGL exam

Solved Papers (upto 2015) SSC CGL Combined Graduate Level Pre. Examination Tier-I
Solved Papers (upto 2015) ...
99.00

SSC Combined Graduate Level Tier-1 Examination
SSC Combined Graduate Level
300.00


SSC CGL 50 Practice Workbook Combined Graduate Level Tier-I Examinatio
SSC CGL 50 Practice ...
314.00


Kiran's SSC CGL Combined Graduate Level Exams Question bank 1999-2015
Kiran's SSC CGL Combined
348.00

30 Practice Sets SSC Combined Graduate Level Pre - Examination (Old Edition)
30 Practice Sets SSC ...
199.00

Exam Process:-

The Examination will be conducted in four tiers as indicated below :

Tier -I — Written Examination (Computer Based)

Tier -II — Written Examination (Computer Based)

Tier -III — Descriptive Test (Pen and Paper Mode)

Tier -IV — Data Entry Skill Test(DEST)/Computer Proficiency Test(CPT) (wherever
applicable)/ Document Verification

CGL Exam Preparation Tips

Study good publication books who focus on the whole syllabus.

For ssc exam some of the good books cover Examrace SSC CGL for Quantitative Aptitude, English and Reasoning.

You can practice RS Aggarwal questions which cover almost all syllabus of mathematics
and S Chand for the purpose of reasoning.

Make your own strategy as per the syllabus.

Study the whole syllabus of CGL tier 1 then

For the better understating, the nature of question paper of ssc exam topic wise, try to involve deeply in previous year papers.

It is best to judge the questions structure or nature of the questions asked in ssc exam.