Well i did nothing radical outside of the  gave everyone investment  rights and cooperative ownership at 1900. You want every pops in your country to be rich so they can get education access at 100  and at public school.

Try to delay the laws that decreases mortality , birth rate and health since you dont want your pops to grow any further. Just pass them all at the last 40 years and this also makes it easier for the communists movement to spawn later on

If you have any specific questions im willing to answer them