The conventional wisdom says, "create something valuable." But good ideas still remain difficult to find. Let's try creating something worthless instead. What do you think will happen?
If you create something and it's valuable to you, you might not exchange it for something else. We see this in trade secrets, closed-door deals, and proprietary technology. Their value decreases the moment they are shared, regardless of the price.
However, if you create a car that you don't intend on using, then you'd exchange it for money (or anything else). Anything that you can create but don't intend on keeping becomes exchangable. Which brings us to our original point.
Instead of creating something that's valuable to you in the hopes of it also being valuable to others, why not create something that's valuable to others even if it's worthless to you?