Below are the important topics for AIIMS

Biology:  Systematics, Genetics, Cells, Ecology and Human Health & Diseases are especially important.

Chemistry: General Organic Chemistry (EXTREMELY IMPORTANT), Hydrocarbons, Equilibria, Bonding etc. Also, be very thorough with reactions of p-block elements.

Physics: Modern Physics, Waves, Heat and Thermodynamics, Ray Optics etc.

All the Best!!

There are numerous important topics suggested by toppers and certain weightages are assigned to each topic as mentioned below.

https://engineering.careers360.com/articles/jee-main-2015-important-topics-books-know-from-experts

https://engineering.careers360.com/articles/jee-main-exam-pattern

There are abundant books available in the market, However some top Books for indepth Preparation are shared below.

Physics:- 

Concepts of Physics Vol I and II by H.C. Verma

.New Pattern JEE Problems: Physics by DC Pandey.

Chmeistry:-

Organic Chemistry by O.P. Tandon

Numerical Chemistry by P.Bahadur

Mathematics:-

Maths XI & XII by R.D. Sharma

All the above books have been recommended by various toppers.

• Because you have enough time, know about the exam very well. Like the eligibility, syllabus etc.
• Create a study table and make it in slots.
• Set your routine in a way that you target the difficult ones first and then go to the ones you can handle well.
• Prepare well, master with basics, keep revising.
• Keep giving online/offline mocks.
• Work on your strengths and weaknesses. Analyse your performances.

For engineering, PCM is required as PCB is for medical courses. And to get admission in B.Tech you will have to give engineering entrances like JEE, BITSAT, VIT etc.

For more information, you can go through below given website -

http://www.engineering.careers360.com

Hope this helps!!!

you should start preparing now. clear your concept first for the maths. you need to prepare your time table accordingly. Dont just read but practice it. be practical. if we consider your almost syllabus is pending then get serious now:p

focus on basic if your focus is BITSAT then clear your basic and practice the BITSAT mock test which available.