The best way of grandparenting is sharing your own wisdom while allowing your child, who is now a new parent, to develop their own. This may sometimes mean accepting different parenting from your own ways.
Some things in the health and research of pregnancy and newborns has changed. 50 years ago most babies were formula fed but now more women breastfeed their babies. A generation or two ago babies were slept on their tummies but now "back to sleep" is known to be safer for babies sleeping in a crib. Bumper pads were normal and now are not reccommended. Co sleeping has controversy but evidence shows that with safe sleep practices co sleeping can be beneficial to families. Many people are certain that picking babies up can spoil them but now we know that babies cry to express a need and that babies who have their needs met are secure, rather than "spoiled".
The bottom line is babies are the same as when you had your children. Society has changed and some research has shown safer practices. A baby needs warm milk, loving arms and family support. It is our job to help our children provide these things to their children in their ways.