hi rahul, you still have 5 months time and if you work smart, you can really score well easily, i will tell you how to prepare

Physics and chemistry- physics is considered one of the toughest subject for medical aspirants,but very interesting. choose any good book of your convinience, there are plenty of good books as many mentioned already. read the concepts thoroughly,understand them cover to cover, if you have doubts, clear them then and there. solve atleast 300 to 500 questions per chapter, check ,analyse and rectify your mistakes. solve again. the more you solve the merrier.initially you wont be getting many correct answers, but as you keep on doing am sure you will see your score rising. solve previous question papers too

Biology- in neet around 300 marks are from ncert text book itself,thats how it was when i gave my exam, so u need to thorough ncert first and then read any good book of your choice and solve as many questions as you can, always stay calm , cool and confident,hope this helps good luck buddy

Hii Rahul, Inorder to score good ranks in the entrance xam, u should start preparing very early.Start by concentrating in the NCERT textbooks especially biology...Many questions ,infact 98% questions are asked directly from this...and u can score a 100% in it...The next thing u should do is to practice many sample question papers by reffering to various guides..U should be very clear in ur concepts..Moreover nothing can beat hardwork...so do work hard and all the best for ur future!!

Here are some tips to help you prepare for major entrance exams like NEET, AIIMS and JIPMER. 

• Make a study schedule: You should prepare a good time- table for your exam preparation. Make sure you include little intervals between study hours. Preparing as per a timetable will help you cover all parts of the syllabus. 
• Prepare as per the syllabus: Before you start preparing for the exam, you should gather complete information about the officially prescribed syllabus. 
• Work on weaker areas: Students are often very strong in one subject and weak in others. You must work hard and try to solve the weaker topics with the help of your teacher, friends and parents. This will let you overcome your fears effectively and help you get better at understanding con- cepts in the future. 
• Gather good study material: Prepare from the list of recommended books that contain the complete CBSE syllabus. To score well, it is necessary to study NCERT as well as other books prescribed for your medical exam preparations. 
• Maintain your health: While preparing for any major medical entrance exam, make sure you take care of your health as it helps you concentrate on your studies. Avoid junk and oily foods and make a strict diet plan. Do meditation and yoga exercises to remain fit and achieve a better state of mind.
• Practice online mock tests: Mock tests can help you crack the medical entrance exams effortlessly. They are available for every subject and cover all chapters and topics. Mock tests will improve your skills, knowledge, performance and time management. Find question papers and try solving them within a time limit of 3 hours to simulate a real exam situation.