How to not fuck up stability?

Hey all. I'm new to the game, just past the 10 hour mark. Been playing as Rome, trying to do a historical run. But I keep finding myself with my stability plummeting and my game getting locked in a death spiral of rebellions. I make care not to go over 50 AE and after every major war I spend some time, up to a decade sometimes, just waiting for my AE to go down so I can conquer some more. Despite this my stability always ends up in the dumps. How do you handle stability? Also, I'm playing with Terra Indomita