Betting on sports will get you a nice investment nest-egg.
But, "richest person in the world" is a tough nut to crack. You are up against not just western billionaires, like Sam Walton and Warren Buffet, but also soverign heads-of-state like the Sultan of Brueni. To be sure you succeed you have to corner a lot of markets.
So, in 1950, there is plenty of money to be made in the sectors of energy, resource extraction, production, distribution, and retail. Not to mention communications and the impending micro-electronics boom.
You have future knowledge, use it. I'm already assuming you've buit up a decent VC nest egg via /u/NotAgainAga recommedation.
Now, you need to start a company that works in silicon-based transistors. The early 1950's are perfect for this Invest heavily in R&D and get yourself some nice government contracts making radios and other communications equipment.
Keep up with the R&D funding, and tell the lab-coats to work on getting the stuff ever smaller and energy efficient.
Set up another R&D operation looking for applications for small transistors - music, phone switching, etc. Corner the market with patents and devices.
By 1960, you have a pretty good fortune. You may want to go the dark route and start taking out smart and wealthy competition. Give this list to your assassins. Or, just hire those people outright and find a way to harness their ambition to work for you instead of competing against you.
Don't forget about energy extraction. Petroleum and coal will do you well to invest in. If you can get a big enough voting share in Armaco you might be able to convince the board of directors to do more outreach to the Saudi people - you know being nice and sharing the wealth a bit with the people who live on the land you are extracting resources from - and create the groundwork for not having the company nationalized by 1973. Do the same in Venezuela and you've got yourself a nice start in the world petroleum markets.
Now, don't forget to option Scottish and Norwegian North Sea petroleum claims and you've got youserlf set nicely.
You want to get some nice North American stuff too? well set up more R&D teams to invent hydraulic fracturing - using high pressure fluid to open cracks in rock and bits of round sand to keep those cracks open. But remember that this is for the future - fracking is only profitable when oil prices are pretty high already.
Use your leg up in electronics technology to revolutionize the retail business, just like Sam Walton did.
Computers, computers, computers. Track the crap out of everything, everywhere. Wal-Mart is one of the most IT focused companies in the world. They pushed for universal adoption of the bar code, did you know that? So they could get accurate from-the-register data about what was being sold.
Create multiple divisions/companies (that you own) that compete in niche markets and in big-box-retail. Also, create the impression that they are against each other so consumers feel loyalty/hatred for one of your chains but not the other. That way they are bound to spend their bucks at one of your outlets.
Don't forget about supply-chain transformation either. Computers and communications dramatically changed the way that warehouses and trucking companies operated. Push early and often for innovations and improvements in the companies you own.
That is a lot of work to do in forty years, a lot of meetings to attend, basically a lot of plates to keep spinning. But if you manage it, you'd have the combined wealth of silicon valley, ExxonMobile, UPS and the Walton family. It would be very hard to dispose you as wealthiest person in the world.
Oh, and if you marry, do not forget the pre-nuptial agreements.