What will increase the CTR of your site?

Hello!
Everyone has heard that small business dies in the first years. Today I will tell you a story from the life that saved my son's business.

My son is 25. All this time he worked as an assistant in a warehouse, but two years ago he got tired of it. He came to me and said: "Dad, I'm tired of working for someone, I'm quitting and will open my store." I was glad about this turn of events. He first opened a small shop that sold vegetables from other farmers. And he received a commission for this. Then he invited his friend to join him, and together they created a website where they could order delivery to their homes, and the farmers would agree on the delivery of their products. After half a year of such work, they decided that they needed to make the business bigger. After graduating from a university they had many friends all over the world. They wrote to them, told them what they wanted to do, and invited them to cooperate. They agreed and they started doing business together. Then they often worked with people from different countries. These are people from Europe and Asia and America. Everyone has their payment methods. As it turned out, this was a hidden problem. Having found a solution, we were greeted.

A year ago, he turned on a great service. It contains all the most popular payment systems in the world. Now his customers have a much easier time making purchases, which increased their CTR by 5%. I think it's cool.

After that, we started looking at what other micro problems his business had. We were very surprised that there are a lot of them, and we did not even realize that this reduces our sales. 

Having corrected his mistakes, he increased his profit by 1.5 times. The solution to these problems was not expensive, but it brought good and quick results.