Mass Communication

First, you should get your hands on previous years papers of the college entrance exams. Try and answer them it will give you an idea as to what line of questioning the exam takes.
In general Mass Communication and Journalism entrance exams test English Grammar, Writing Skills, Knowledge of Current Affairs and Critical Writing ability. Critical writing is not criticising but being able to grasp and break down a problem to explain it then offer probable solutions or answers.
Reading newspapers, knowing the media landscape, watching news television and trying to understand why Arnab Goswami shouts so much, why newspapers write in a certain way and why news on internet portals is so different are some of the things that you may need to know an answer. There will be questions on Media Policy, Laws, Ethics, Films, Books, controversies, free speech, election propaganda, news coverage and so many other things.
After getting through the entrance test there will be a personal interview which will test whether you have the content to back up your statement of purpose from the test. Basically, you need to know everything under the sun. Sounds intimidating and it is but it is not impossible.

Hi,
First, learn to write, report and edit. Being able to tell a concise, interesting and informative story is the same whether it is a school board meeting or a baseball game.
The world is filled with sports junkies who have dreams of being a sports journalist, but who are unwilling to learn the craft of being a journalist first.
Once you have polished your journalism skills find your local community newspaper or radio station with samples of your work and offer to work for next to nothing.
If you are lucky they will bring you aboard and you will get the scut work, but over time you will move up and earn respect.
Moreover, pursue a mass communication degree to get the details about journalism.

First things first, I would like to applaud you for the fact that you have realized your "real" core interest and want to pursue it as a career. This is a brave thought and requires real care, focus and planning. I would suggest you should take a pause, think and then act so that you have enough time, information and facts before you make any decision.
Next, how to go about it? We need to keep a few fundamental things in mind while we think, plan and act on such a career change move. Here are some tips:
1. Even if you are well off financially, first identify the source of your bread and butter. I believe, for you it is your medical profession. So continue to work hard in this domain. Do not blink.
2. You can approach it in two ways: (a) First become a host of any show and then move into travel specific profile; Get into travel industry and then move on to become a host.
2. In order to achieve this in an organized manner: Create a project plan with specific dates and goals. This has to be a research project where you will find out the career options in the "Travel" industry and specifically the opportunities to be "Host" of a "Travel Show". You will need to dig information from all possible sources. By the way, you are already doing it by asking this question on Quora. So continue to dig information from all possible sources, viz, Internet, Friends, Acquaintance, Books, Newspapers etc. Please note you need to execute it as a time bound project.
3. Once your research project is over(within the timelines originally set), the logical next step is to ponder over the outcome and find out the "real" and "viable" options that you can pursue. The result may give you range of opportunities. You may want to first get into the travel industry in the best profile "available" and then look for being a "host" OR you may first opt to become a "host" and then look for hosting profile in travel domain.
4. As mentioned in Step 1, while doing this research you are still continuing your medical profession so whatever research you do is going to be an additional effort on top of your day to day job. This is going to test your patience, energy level and passion for changing to a new career stream.