How to start a online shopping site

My friend called me and said "I want to sell my work on the Internet. What skills do I need to run my site?" I explained to him how to start. Then I told him about the services he should pay in order to make his business work. "At first you have to get a computer and then have it connected to the Internet. You need to get your own website address and make a contract with a shopping cart service and a payment service. You should be able to use Photoshop to process photos. You should also be able to make good catchy lines. Creating htmls are also necessary. He said to me "I have to do a lot of things. I want to have my website. I will start with the things as soon as possible. I'll call again." I hung up the phone. After I hung up I thought about his question of what is necessary in order to begin his site. Then I noticed two things. The first thing is that you should keep running your business for 3 years even if there are no sales. Another skill is that you should try to do everything and anything that might make it possible for any sales. He can get any skills apart from these two. I called him again and I advised him with these two skills.