Well, if I am about to start a project, I always try to understand the scope as much as I can. I know it might change due to many things you will discover, but still I think it is a good idea to know where you will step into.
Who is going to use? What are their goals/needs?
If you don't know who will use, you won't be able to get precise information. Maybe you will discover that your initial target was not the right one.
What is the problem I am solving? What am I trying to achieve?
Of course you can start a project just because you think it is cool. But, I always try to understand what are the pain points of a process or use, or what is the desired outcome so I can think of possible sollutions to the subject.
Where will my project be used?
Here don't think only about devices. Think also about places or situations where it will be used. Street, bathroom, home, work, TVs in a store etc.
Of course it is not a exhaustive list, but it might help.
Best wishes and good luck.