Brian Kelly realized he had a knack for maximizing credit card rewards when he was working in HR at Morgan Stanley.

"My job was to go to around to all the college campuses and recruit the top computer scientists to join the bank," he tells CNBC Make It, "so I was traveling like crazy, racking up tons of points. … I was traveling around the world to places like the Seychelles for free and people were finally like, 'What trust fund are you on Brian?'

"There was no trust fund — it was just my points."

In 2010, he started a blog to share his best travel and points advice. What started as "just a fun little side gig," says Kelly, evolved into a lifestyle media brand that reaches millions of people across social media platforms and the Points Guy (TPG) website. Kelly quit his corporate job a year after his first blog post and sold the company to Bankrate in 2012, but he remained CEO.

Today, he remains the CEO of TPG and travels the world for next to nothing, thanks to the points he constantly racks up.

"I've got 25 credit cards and a near perfect credit score," Kelly tells Make It, "but that's because I really manage them. … A key thing with earning points through credit cards is you must pay your bill off in full every month. Otherwise, the interest that you pay will negate the value of those miles and points."