Unless you are starting a personal project, the first thing you should be doing is writing a document with your thoughts about the project.
The more I work with different systems and businesses, the more I see that documentation around the project is always missing. I know it can be a daunting process to write all thoughts and strategies, but maybe we can start focusing on these two things:
- The system’s overall goal and why we are building what we are building.
- Why did we add X feature to the project, and when was it added?
When onboarding someone new or handing over the project to someone else, this could be a good base to help them understand your business/project—a good starting point for them to ask questions.