As you said you will appear in Elitmus test and looking for good books for its preparation , so on your demand here I am providing same for you :

How to Prepare for Quantitative Aptitude for CAT by Arun Sharma

Logical Reasoning by Arun Sharma

Best English Section verbal ability Book

Quantitative Aptitude by Arun Sharma (But just practice Level 1 & 2 only)

Verbal & Non verbal reasoning by RS agarwal.

Some points you need to keep in mind to get good marks

1. Paper level is very tough. elitmus exam is a mock for CAT students.

2. Don’t try to attempt lot of questions.

3. 10 per section in elitmus is ideal attempt to exam.

4. For problem solving section, best scoring part is cryptoarithmetic questions. Try as many question as you have. For crypto arithmetic question don’t refer any books. Just follow this site

If your cryptoarithemetic questions are correct then your problem solving section is completed. In DI problem, you can’t write all the questions in time. It is highly impossible.

5. For verbal section, best scoring area is ‘verb form’ type questions. For example download elitmus paper. Now, coming to paragraph questions. Almost 12 questions are there, it is the best scoring area.

6. For quant section, nothing I can tell about quant because it’s totally jumbles. They cover almost all topics.