Every person has their own area of specialization. You need to start a business in which you are perfect or think you are better than others the reason behind this that only those businesses will be successful who managed by dedication, hard work & consistency. And you will be consistent in only the business or work whom you like to do not force to do. If you run your business just because of doing business like others. It will not work so my suggestion that Makes your passion as your business. If you need more detailed guidance I m all here to guide you in all the way.
Such as if you are a good salesman. then Start Marketing company and do the marketing.
So it depends upon you. And even still you need normal advice open online selling business will be much better than other businesses.