I thought I'd start something here regarding 529 accounts and general tips & tricks. So feel free to share or ask anything.
For my part -- Consider Qualified and Unqualified Expenses & have funds for both
We have 529 accounts for our two kids. Now that the first one is in college, it is obvious that we saved a bit too much inside his 529 and not enough outside of it. He got a scholarship (a good thing) that reduces the qualified educational expenses to below what we have in his 529. However, he lost the "on-campus housing lottery" (a bad thing) which means he'll be off-campus over the next three years and we'll be carrying the unqualified portions of his living expenses from our savings. I only share this to suggest that it might have been better to set up a separate taxable account to accompany his 529 and maybe split the funds 80/20 between 529 & taxable. This arrangement would have allowed me to draw only from funds dedicated to him.