Grandma L has three kids, seven grandkids and two great grandkids. She is French and moved to the US when she was just twelve with her mother. Here advice was:
You don't want to be too strict. Her husband was very strict and she was the counterbalance to that in her family. She also has one son who spoils the kids. They get whatever they ant. You have to keep a balance between being strict enough but also not spoiling your kids.
Spend time with them:
She also advocates spending good quality time with your children. Too often life gets in the way, but time with the kids is what they really crave and what will serve you and them well.