Inverted is ballsy! It's actually much more stable, but the giblets interfere!
It's easiest done low so you can see your corrections and quickly adjust as needed. My biggest tip is to first make sure you are using a plane that does it well, then constantly blip or pulse the throttle. That pulsing makes sure your corrections are getting good airflow of the surfaces. Angle of attack is different with every plane, but once you find it, it just takes lots and lots of practice!
I learned inverted pretty recently and it's what I do the most on the sim right now. At first it was extremely difficult, but like everything else, it seems much easier now that I've logged a few hours of constant inverted harrier on the sims in outside!