[Non-Tech People building Tech Startups] What are your biggest pain points? I will not promote anything

In terms of tech,

1. How do you validate technical feasibility?
2. How do you build an MVP?
   
3. How do you find early set of users? How do you validate market needs?
4. Let’s say the validation stage goes well, what can lead to startup still failing.
5. What are your biggest pain points in the journey?
6. What are the most common mistakes that you have done?

Overall I am trying to understand what to do and what not to do as a non tech founder building tech product to maximise the chances of success