We've had a 529 plan for years for our 14 yr old daughter. There are a lot to choose from so do your research.
We also have a regular savings plan as well as other investment plans (coins, savings bonds, real estate, etc) in place to cover her college and our retirement. Make sure you are diversified and all eggs are not in 1 basket!!
If you don't already have one, I would suggest a financial officer you trust to get some guidance. Many people are "selling" these plans and they get profits everytime you invest. Just be wary....
My hubby is a numbers man...he lives and breathes numbers, projecting and estimating.... even with his knowledge and experience, we still worked closely with our Edward Jones rep to make sure we were looking at all details of the plan.
Good luck! It is a lot of info to sort through but kudos to you for looking out for your children's best interest in getting them educated.