I have a semi flat roof and I purchased a number of "Hula Hoops" to place up there. I painted them bright Orange / Pink, and mounted them on a few bricks to hold them upright. It creates a really cool "track" for you to fly through in FPV and hones your flight skills.
If you use the TelloFPV app, you can try the different modes: Sport, Video, Cinematic. Each has it's own characteristics and I have recently found it fun to make cinematic videos with the Tello. (it's a fun challenge in a slight breeze! - Mind the trees!)
Want to go further? I've been experimenting with a dual repeater setup. While you won't be able to go higher than 30m, this should increase the range wherever I can plop a repeater down.
- Adi