Business relies on how good you are in convincing them to buy your product.
In simple term, Marketing.

Marketing refers to the activities of a company associated with buying and selling a product or service. It includes advertising, selling and delivering products to people.
source: https://www.investopedia.com/terms/m/marketing.asp
On our Principles of Marketing subject, we are taught about how hard marketing is.
As a good marketer, you should make money come into your business.
There are eight functions are essential to the marketing of all goods and they are:
- Buying
- Selling
- Transporting
- Storing
- Grading
- Financing
- Risk-taking
- Securing market information.
Without marketer, there are no sales. And without sales, business will lose its essence.
Never belittle a Marketer.

