Most things fail if you don’t spend enough time with them. The sheer amount of time this thing spends in your head is very important. Sometimes it appears as an obsession. You can't not think about it. Other times you have to will and discipline yourself to spend time with it. It is important that it is present in your mind.
All successful things have one thing in common: a champion. A champion is someone who spends energy in order to move things forward. It's someone with seemingly inexhaustible amounts of agency. Someone who cares unconditionally for it to succeed.
You need to work on it. This work is not the same thing to all of us. Some of us work by thinking. Some do research. Some create. Some manage. Whatever work is yours, it needs to be rendered fairly often, and at various intensities.
You always need a little bit of luck, so stay lucky.
The part about luck was added based on the excellent observation and input from Maja Kovačević on LinkedIn.