Most often, investors are not people from the restaurant sector. There are no two owners in one house, and you need to discuss on the shore that all decisions remain with you, otherwise there is a chance of losing your business.
The main thing in the partner is an adequate perception of the project and trust in you. It is much easier to work with a person who will fulfill his part of the obligations well than with someone who will try to do the work for you. And of course, there must be a common understanding of the project.
For example, I was lucky with partners, we look at things the same and respect each other's business space, and I really appreciate it.
Unfortunately, not all errors can be quickly corrected in the process. For example, if you signed up for a high rental, then the cost is unlikely to decrease. If, for example, you choose an unsuccessful location, finding a new place and moving requires a lot of money and time. In any case, if you have a goal, do not give up on it, you just need to understand - if something does not work, you need to go in other ways.
If you are aware that you are at a dead end, you do not have enough strength and knowledge, be sure to look for information - there are many specialized events with interesting speakers, lectures, forums, restaurant conferences and much more. As for the individual consultations of specific restaurateurs, here you need to try. Such people really value their time and are not always ready to give free advice. But, I repeat, be sure to try. Someone will refuse, and someone will give advice.
If it seems to you that everything is going wrong, take a break. Nothing terrible will happen. A person needs to gain strength, emotions, perhaps rethink something or be alone to think things over, weigh and understand what he is doing wrong. Most often this happens when emotional burnout occurs and a lack of energy is felt. After a pause, you begin to understand what needs to be done next.
To prevent the most common mistakes, I would advise newcomers to still have a managerial (not necessarily restaurant) and communicative experience. You need to be able to properly build relationships with partners, employees, investors.
Build a strategy for the next few years and move from step to step only when you understand that at a particular stage you have solved all the tasks.