Indian Engineering Services (IES) is a national level exam which is conducted every year by UPSC. 

The following tips you can follow:

Firstly go through the syllabus of each paper of IES exam which you get in detailed notification of IES released by UPSC.

Go through basics of your core

GK Syllabus is kind of infinite so there is noa ny particular book for this. The exams of SNAP & IIFT has different type of GK questions. Here are some preparation tips you can prefer.

Read News paper daily

Go with current affairs & Magzines

Make notes on current Events

You can recommended below books for your preparation

-A Complete Success Package for Online BITSAT (With CD) : Comprehensive Coverage of NCERT Syllabus for Classes 11 and 12 (English) 4th Edition- Arihant Publication

-BITSAT Explorer (With CD) (English)- MTG Editorial Board

-BITSAT English Proficiency & Logical Reasoning PB

You can consider below names -

MHTCET BOOKS-
MHT-CET Engineering Entrance Exam Author: Editorial Compilation
MHT-CET- (Cd Rom) Author: Upaveda Learning Solutions Pvt. Ltd.
MHT CET – Chemistry (Marvel) For XII Science Author: Mayur Mehta, Chitra Joshi, Rekha Diwekar
MHT CET – Physics (Marvel) for XII Science Author: Bapat
Physics(Volume

All is required hard work detemination and focused on your goals 

First i would recommend that you go through NCERT books thouroughly that will buid your base if you have your grip on ncert then you can do wonders in jee aswell as neet.

Then after this do any mcq

 One of the important aspects of the preparation strategy is the syllabus. Youl should know what are the topics from where questions will be asked. This will aid you to plan your preparation.


BITSAT Syllabus for Chemistry;


Hydrogen and s-block elements; Chemical Bonding & Molecular Structure; Principles of Organic Chemistry

You can download the sample papers from the given below link for your practice

NEET Sample Papers

Good Luck!!