>>3462543Just learn to fly and especially make smooth, tracking turns and orbits. That's a huge as fuck differentiator.
If you really want to spend money, get any of the books that talk through exposure (Brian Peterson's Understanding Exposure is pretty good, but he takes some liberties with how he talks about some of the stuff).
I HIGHLY recommend doing something like Phlearn or the Adobe courses on doing post processing. This is another huge thing a ton of real estate photographers suck ass at. If you're also going to do interior shots and you learn how to properly HDR photos, you'll be a fucking king (emphasis on /properly/)
Now the above stuff, you don't have to spend a dime on. There's tons of tutorials out there for free. You'd probably be better served getting some speedlites and a remote tx for interiors.