My sister gave IIIT Hyderabad PGEE Exam in 208 and claims it to be easier than GATE. The number of questions varies every year but the pattern somewhat remains similar. The exam had two papers.

Paper 1 - Aptitude (Time: 90 minutes)

• This one comprised 40 questions out of which 20-25 were quantitative questions, 5-10 questions were based on programming and mathematics, and 10 questions were based on comprehension
• Some of the most common topics covered were Calendar, Clocks, Directions, Blood Relation, Time and Distance, Probability Syllogism, Number and Series, Data sufficiency, and Propositional logic.
• As a whole the level of difficulty was easy to medium. 

Paper 2 - Technical (Time: 90 minutes)

• This paper comprised 60 questions out of which 20-25 questions were from previous years Gate/Isro paper. The remaining questions were related to simple subject knowledge. 
• The level of programming questions and data structure questions was higher than in the Gate exam.
• Each question had more than one answer and not ticking all the right ones would lose you marks. 
• Again, the level of difficulty was easy and anyone who had cleared GATE could clear this too. 

It's best to adopt the same strategy you used for GATE preparation and you will surely get good results.

After doing some research online, I gathered some information regarding your question. Let me mention these which you can later analyze and check if it is useful or not.

• It is an online MCQ-based Post Graduate entrance exam for direct MCh Neurosurgery, DM neurology, and MD Psychiatry courses.
• The exams are usually held in the last week of March.
• It is a 2-hour long exam and comprises 150 MCQ-based questions.
• 1 mark is given for every correct answer and ¼ mark will be deducted for every wrong answer.
• 90-100 questions generally come from the routine subjects studied during MBBS. These are similar to the ones asked in other entrance exams like AIIMS and JIPMER.
• 50-60 MCQs are related to Neurology sections of all other subjects like anatomy, physiology, biochemistry, microbiology, pharmacology, pathology, ophthalmology, medicine, surgery, psychiatry, radiology, and anesthesia.

For preparing Neurology you can take help from the following books:

• Harrison for Neurology
• Ganong for Neuro-Physiology
• Snell's Neuro-Anatomy
• Neuro-Biochemistry from Harper
• Neuro-Microbiology from Paniker
• Neuro-Pharmacology from KDT
• Neuro-Pathology from Robbins

Try solving the previous 4 to 5 years of any NIMHANS MCQ guide. Also, try to score 120-130, this will secure your place among the top rankers.

IIIT Hyderabad conducts UGEE for UG admissions and is somewhat like JEE. The syllabus is usually from Ncert +1 & +2 Books, from the PCM subjects. If you are well-versed in your basic concepts clearing this exam won’t be a hassle. It’s however recommended to procure some written modules of certain Coaching materials the best being IIITprep.

IIITprep has excellently written content that helps you prepare well for the exam. You can even download the available PDFs and books from its website. The topics covered give you a better understanding of the complex topics. In fact, the course material is so good that it helps you in preparing for JEE Advance as well. 

So for cracking UGEE, refer to the material from IIITprep and you are good to go!

The OUAT entrance questions mostly come from NCERT books. Especially for the Biology and Chemistry section. So, cover all the topics from NCERT Biology and Chemistry. Along with that solve the previous year’s questions. Also, you can buy an OUAT entrance guide. You should make a habit of solving 200 MCQs within 2 hours to prepare for OUAT. 

Basically, there are 3 rounds to enter NICMAR:

1. Written: The written portion is identical to any admission exam that includes aptitude and grammar. Read books by RS Agrawal, and you'll succeed.
2. Group discussions: GDs typically centre on current events or hypothetical construction or project situations. For the GD, you can start reading the newspaper carefully a few months before the test. There won't be a clear trend in the topics discussed, but most of them will be current.
3. Personal Interview: You may be asked general questions on HR, technology, current events, and other topics.

Advice: Be self-assured and communicate effectively.

Irrespective of the fact if you are a dropper or not, admission to AIIMS requires excellent time management skills and mastering the 4 Ds; Determination, Dedication, Discipline, and Desire. Your quality of study matters more than your quantity. Here are a few tips that will help you crack AIIMS Delhi.

• Mastering the NCERTs is going halfway through the AIIMS entrance exam preparations. Almost 90% of the exam is from NCERT, even the diagrams and reasoning. 
• Focus on quality rather than quantity. Stick to one book but revise it thoroughly.
• Practice OMR and improve your time management skills.
• Enroll in some coaching institutes and sit for their online exams.
• Give equal attention to every subject. Don't do selective study. 
• For the GO pet, the best way is to read 30 minutes of newspaper and note down anything you deem important.
• For the aptitude part enroll in Allen AIIMS as their question papers provide good G.K and aptitude. 
• H.C Verma is the best choice for Physics combined with MCQs from D.C PANDEY.
• For organic chemistry, go through GOC and named reactions. NCERT is enough for inorganic and Narendra Avasthi for physical chemistry.
• For biology, NCERT is more than enough.

Lastly, stay positive and motivated throughout!