Most of my seniors said study hard for your entrance exams since its so hard to crack them. I'm sure most interns would study anyway as a default. I wouldn't stress on that aspect.
I would say use your internship to prioritize your career goals.
What do you want to be?
Sometimes this question is asked too late in a medical student's life.
To prioritize your medical career you need to use your internship as career sampling.
More than knowing what to take as a specialty you should know what not to take.
Few things I think might help you in that
1. Keep an open mind.
Never get bogged down by other people's opinions about what you should do. What you do is your business not your uncle's or neighbor auntie's.
2. No work is too small.
Take up every role that you come across. Cleaning a colostomy tube is as important as putting in the colostomy tube through surgery.
3. Respect the patient.
Work towards making them better always and try your best not to hurt them. Always remember that patients are your best teachers so give them as much respect as you would your teachers.
4. Take ownership of your patient. You might be just an intern who follows your unit head's orders but the patient is still yours. Try to create a personal bond between you and your patient. It always helps you and the patient. Both sides get what they want.
5. Medicine is art.
Work hard in the wards. Your books will only take you so far but the warfield (wards) is where you learn the craft. Never belittle any ward procedures. IV lines, central lines, urinary catheterization ,repair of emergency lacerations..... You never know what you will come across in the wards. These skills you can never acquire or experience later. I did one central line during my internship and that experience was exhilarating. Being an ophthalmologist now I'll never do it again so I'm thankful I did it then. Wards and patients will give you all the inspiration you need to propel you towards a speciality. One such memorable experience: Raghuraj Hegde's answer to When did you realize that you've become a doctor?
6. Make your peace with death and disease.
Until you reach internship you never realize how much death and disease of your patients can affect you. This is because you will have a personal investment on the patient. You will sometimes feel helpless in the face of mortality and morbidity but that is necessary.
7. Find your role models.
It could be anybody you work with and even your own batchmate who has probably figured it out better than yourself. One is never short of people to look up to.
8. Recognize the wrong people.
You will come across people who are not good at their job, people who insult and look down on their colleagues and juniors, people who are unethical and so on. Identify those people and make note to yourself never to be like them. Do not let a bad doctor ruin a good speciality option for you. I didn't have good teachers for ophthalmology in my medical school but I didn't let it spoil my opinion of ophthalmology.
9. Maintain your sense of wonder
I feel we need to find wonder in what we do and work towards what we want to be. I would advise the same during one's internship. Never lose that wonder.
Good luck. Always remember you will never get to be an intern ever again. Use it well
Disclaimer:
This answer is not a substitute for professional medical advice. This answer is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor or hospital immediately. Always seek the advice of your doctor before starting or changing treatment. Quora users who provide responses to health-related questions are intended third party beneficiaries with certain rights under Quora's Terms of Service (http://www.quora.com/about/tos).