Among the causes for a project is not concrete, a not valid business model, problems with partners, and difficulties in team management. What were the reasons why your business idea or venture did not work? You have to make your retrospective in order to find out exactly what fails at the end of your process of having your own business.

Here is a list in which you can think about the main mistakes you may have committed to make your entrepreneurship to fall down:
Do not validate the business model.
Many entrepreneurs believe that they have a good idea and without thinking twice they plunge themselves for it. They develop a product, hire staff and end up seizing their lives for many years if this idea goes wrong. Although this attitude is very praiseworthy, a good entrepreneur will always validate their business hypothesis before launching into the arena. Before investing time and money in developing a product or service, we must do research on the market needs, and the competition, make interviews with potential buyers or even make a MVP (Minimum Viable Product).
Partner Issues.
Partners are another major failure problem. And is that co-founding a company is almost like a marriage (but without sex). You are going to spend many hours with the other person and you are going to have to put a lot of confidence on it to make everything work.
If something goes wrong-you can say goodbye to the company. Often entrepreneurs make the mistake of looking for a partner solely because of the fear of undertaking alone (error). In other occasions partners are only taken just because they are friends or relatives even though they have nothing to contribute to the company (error). And many times, partners are taken only because they do not want to hire someone to do certain tasks (error); a partner will become the most expensive employee you have ever had. You are going to have to split the benefits with him/her.
Difficulties in team management.
A person can be very good at undertaking, but a disaster in team managing. This is often one of the main problems of failure. When a company begins to grow and the team increases, an entrepreneur can be overwhelmed by the difficulties of coordinating a team.
It is for this reason that in many Startups, when you grow enough, the entrepreneur has to hire a person to assume the responsibility of being a CEO. There are tools like Tribe Scale very useful in team management, but even so, all the training that an entrepreneur can acquire in this area will be little.
The difficult thing is not to entrepreneur, but growing.
After the entrepreneurial phase begins an even more difficult sentence: The growth phase. While in the first phase we may have had some source of external financing (loan, credit, personal savings …) in the growth phase we will have to start showing results, i.e. benefits.
Many entrepreneurs forget this and try never to leave the entrepreneurial phase. It is true that large Startups have achieved great achievements without ever giving them benefits (only because of the potential they had for their investors), but this is not the general rule. A business that wants to work must demonstrate benefits and the sooner the better. If an entrepreneur loses this view, it may be too late when he/she wants to realize that he/she is going downhill and without brakes.