Which type of knowledge, One should start gaining? If he/she want to start their own business and they have just started their college.

KNOWLEDGE ABOUT THE MARKET

The main knowledge one needs to gather is about the market they are diving into. India is a vast country and with various markets. You got to be knowing about the market you will be dealing with as well as the connected ones. How can an another business affect your business? One needs to understand that everything is interlinked and one thing leads to another. Just starting your own business without any prior research won't do you any good. Ask out the people who are involved. Ask your parents as well. Discuss with various people. Know their opinions. Try to gather the statistics over the past years. If you think people are going to love it or support your idea then go on for it. 

TARGET AUDIENCE

No business will run without customers. You just can't invest and sit back and earn nothing. You should know your target audience. Whether it is the students or the adults or the aged ones. Try to organise a survey. Ask them questions, what do they think about your startup? Is your business idea still in trend? What are their expectations? Your business can be anything, online or offline. The youth prefers the online mode whereas the aged ones are more comfortable with the offline market. 

MARKETING

Which strategy are you going to use in order to spread the news of your startup? Will social media marketing and digital marketing work for you? But what about those who are not available online ? Is it some area specific or applicable all over the country? Will newspaper advertisement do the job for you? Ask yourself these questions. Marketing is a very crucial part of any business for any age group. 

These are the primary knowledge one needs to gain. If you are ready for these, go for the next step, that is execution.