The best way to star earning passive income is with affiliate marketing.
Amazon is the biggest online marketplace and you can earn a percentage on each sale when you promote a product using your special affiliate link.
But you have to get the right people in front of the right offer.
If you love digital cameras, you can use youtube to attract people to your video. Do a product demonstration and make sure you have your amazon link in the description of the body.
Video on youtube will last forever and will earn you daily passive income.