Not understanding the customer...
In reality, all business owners (most of the people that Minh has come into contact with) when starting up, never really care about this issue. At best, they only have a superficial understanding of it.
For example, if you sell fashion clothes, then customers like beautiful, unique, and stylish clothes, that's all you need to know. You will order some trendy items to sell and then just stock up on inventory.
Many people fall into this trap, so if you are new to this and see yourself in this article, then sit down and have a piece of cake and a cup of tea.
Seeing something hot and thinking that many customers will like it --> buy it
Seeing someone else selling well and thinking that you can sell it too --> buy it
Seeing the whole community going crazy for it (like masks recently) --> buy it
Having too much money and not knowing what to do with it, so buying things to sell for fun --> buy it
Hearing friends say that a product is good, so buying it together to sell --> buy it
....
Buying until dead...
And certainly, you cannot succeed because you simply do not understand why you are doing this, just for money...
First, understand yourself