General concept is working hard
The harder concept is the supply and demand
Look for what the people want most, then try to sell that.
Like I don't just do one type of business, like clothes yea I can easily sell clothes, Yeezy's are in big demand right now so I can sell shitload of those, so are a bunch of other clothes/shoes/ accessories, lots of people want it, but I also do electronics and the stock market, etc.
Soon Ima start making apps/ programs with advertisement revenue
Don't expect to get rich quick because everyone wants that but that's not possible unless you create something out of our generation which I highly doubt.
I don't like to stick to one type of business, why make income from one place when I make it from multiple places.
Especially when it comes to SE, like why would I sell it for 10% of the products value when I can get it to myself and sell it for more than 95% of the products value.
Only selected few I've actually given them such a low percentage because I'm a nice guy.