Hello aspirant,
You can try for entrance exams like TS EAMCET, KCET, AP EAMCET, BITSAT, VITEEE, etc to have a practice of entrance exam and syllabus will be similar though the difficulty level is less than JEE exams but can give a practice and experience to you.
Best Books for preparation of JEE exam are listed below.
Physics:
NCERT Physics Class XI & Class XII
Concepts of Physics by H.C. Verma
Chemistry:
NCERT Chemistry textbooks for Class XI and XII
ABC of Chemistry for Classes 11 and 12 by Modern
Organic Chemistry by OP Tandon
Physical Chemistry by OP Tandon
Mathematics:
Mathematics by Arihant Publications
Objective Mathematics by R.D Sharma
NCERT Mathematics Class XI and Class XII textbooks
To get more information go through below mentioned link.
https://engineering.careers360.com/articles/best-books-for-jee-main
For JEE sample question papers go through below mentioned link.
https://engineering.careers360.com/articles/jee-main-sample-papers
You can check below given link to get free mock tests for JEE
https://engineering.careers360.com/articles/jee-main-mock-test
Also, visit below mentioned link to get more information about JEE Mains Knockout.
https://learn.careers360.com/knockout-jee-main-april/
I hope this information will be helpful to you.
Good Luck!!