Dear Chirag,

It is recommended to start your preparation for NEET after completing your 10th class alongwith your 11th and 12th class. so, that there is no gap between your studies.

Syllabus of NEET exam is same as your 11th and 12th class so you can easily prepare for it. 

If you want you can join coaching institute or you can prepare by your own.

You can make your proper time table it will help you to complete your course on time and you will also get proper time for revision. 

To score good marks make sure you complete your NCERT books, Previous year papers and solve as many as mock test series for your practice.

You can focus on the topics which carries more weightage in the exam.

All the Best!!