I am Studying in 10th Standard.. I wish to become a Doctor. How can I start preparing from Now onwards?

You need to select Biology (Science) as your subject in PUC. After that, you need to write the CET and clear the same with a better rank to become a doctor.
Medical is one of the most sought out profession in India. Along with Engineering, MBBS is preferred profession for Indian students. To become doctor you will have to take the science stream for Class 12th. To get admission in a MBBS college you will first have to appear in one of the several medical entrance exams.
This is the most difficult part because there are only couple of thousand medical seats in India for which more than 1.6 million people apply. Therefore getting admission in the MBBS college is not as easy as it may seems. Thousands of people fail to crack the entrance exam. It would require months of preparation and professional coaching to crack any of the medical entrance exams in India.
Here are some of the entrance exam where you can appear:
CBSE PMT
One of the most popular entrance exam for MBBS is CBSE PMT. Also known as the AIPMT, this exam is to fill 15 percent of government quota seats in MBBS in India. There are two parts of the CBSE PMT exam. First one is Preliminary exam which is followed by the Main examination.
AFMC Entrance Exam
AFMC means Armed Forces Medical College. This entrance exam is for 130 medical seats in Armed Forces Medical College (AFMC), Pune. Thousands of candidates appear for the 130 available seats every year. There is one condition for candidates who wish to complete MBBS from AFMC. They will have to work as Commissioned Officers in the Indian Army for at least 7 years. This is the part of the agreement which can't be violated later.
AIIMS Entrance Exam
Another prestigious exam in India is AIIMS entrance exam which also offer very few seats but despite that thousands of candidates appear in the examination.
DUMET
Delhi University Pre-Medical Test also known as DUMET is the medical entrance exam for the MBBS aspirants. This exam would give you admission in medical college affiliated to the DU.
JIPMER Entrance Exam
Jawaharlal Institute of Post-graduate Medical Education and Research also offer 75 MBBS seats every year. To get admission candidates are required to appear in the JIPMER entrance exam. The eligibility for exam is at least 50 percent marks in English and same percentage for Physics, chemistry and biology combined.
Apart from these exams, you can appear for the several state based medical exams like CET for admission in the MBBS college.

All the best.

You will need to focus on stress and time management. In order to manage stress you have to manage your time wisely. <span style="background-color: transparent;">You have to set a routine for yourself and stick to it for the most part. Once you get into the groove of a routine it will be much easier for you to manage your time and have enough time for everything you need to do (including relaxing). Make yourself to-do lists on a weekly basis, use Google calendar or a planner to keep track of events, deadlines, and due dates. In addition to setting a routine and sticking to it, plan out relaxing activities into your day. Or set aside a time, after everything is done for the day, that you can have "me" time. I have also personally found it essential to not only find time for myself but also make use of that time in a way that is best for me and my holistic wellness. I have found the HeadSpace app to be an essential tool in helping me relax and generally feel more relaxed throughout the day, Guided meditation, even if you have a busy schedule, will make you feel more at ease and relaxed throughout the day as a whole (not just when you have the time to relax and focus on that "me" time).</span>

<span style="background-color: transparent;">Set a routine.Use Google Calendar.Set aside Me TimeWrite weekly to-do lists and use a planner.Find a peaceful and restful activity that will help you feel relaxed.</span>

<span style="background-color: transparent;">Here is how to be successful in them:</span>

1. <span style="background-color: transparent;">Stay on track - do assignments early, finish things a head of time, and be aware of all of your deadlines</span>
2. <span style="background-color: transparent;">do all the the assignments and read all of the coursework required- do not cut corners</span>
3. <span style="background-color: transparent;">use Google calendar to keep track of deadlines</span>
4. <span style="background-color: transparent;">communicate with your professor early if something comes up</span>
5. <span style="background-color: transparent;">do not be afraid to ask for an extension if you need one</span>
6. <span style="background-color: transparent;">study, and study a lot! you don't have regular class sessions so you will need to put in more work at home.</span>
7. <span style="background-color: transparent;">Do your best and genuinely try hard to give it your all.</span>

The best way to score high on the test is to Google search an online program or book that will help you study. Once you find an online lesson plan for success you can use it as a road map for studying. Otherwise, find a book to help you study and spend 45 mins a night reading through it and studying. Depending on when you test is, the first thing you will want to do is organize a studying schedule for yourself. Target studying certain sections of the test and divide them up by the weeks/months you have until you have to take it.