How do you make Mexican Rice well?

This is pretty embarassing, but each time I try to make Mexican (Spanish/Red/etc.) rice, it never works out. I fry it lightly in olive oil, and then boil it in watered down tomato sauce (and garlic and green onion,) and let it cook for around 50 minutes (or whatever time is appropriate,) but it never seems to absorb the water properly. I’ve tried this with white, wild, and brown rice, several times each.

I know it works because I’ve seen my mom make Aroz con Pollo and Mexican rice successfully, utilizing the same process.

Am I just cursed?!?