Need help with listening to Mozart.

I mean it’s easy with Beethoven, he has symphonies 1–9. You can hear a sort of progression of his styles from first to last. But with Mozart, he has thousands of compositions. I don’t know where to start. What am I listening out for? Did he have certain periods? I’ve heard a lot of his music and it’s all good, but I can’t get a handle on his body of music as a whole.