What do you do best? You know the answer.
You know -- that thing your friends are always telling you you should be doing for a living. That thing people call you and seek you out to ask about. That thing you spend time doing when you're not doing the things you have to do.
Start doing that thing.
Do it a lot. Put it online and share it. Then sell it. Then tell people what you've done and build a brand a business around it. How? By doing that thing as much as you possibly can.
As much as you possibly can? Yes.
Wake up 30 minutes earlier or go to bed 30 minutes later.
On your lunch break.
Let it replace that TV show you're always watching that does nothing for your development as a person.
Google search a person who's already doing it and find out they got started.
When it's all over, most of the details of you will be forgotten. Your life will be a snapshot of what's important about you.
Make sure the camera catches you from the best angle, in the best light.