My tips are to find a daycare with a preschool curriculum, as noted, and to split the day with your partner. One of you goes to work as early as possible--try to get to office by 7:30 or 8. Leave at 4 and pick up kids by 5. The other spouse drops kids at daycare around 8:30 or so in the morning, gets to work by 9 or 9:30, and leaves later.
This way, the kids are only in "school" from let's say 8:30 to 4:30 or 5 (and they'll have nap/rest for a few of those hours). Plus you each get time with them in mornings or evenings.
This is, of course, dependent on having a not-terrible commute (we make it work with commutes of 45 minutes and 20 minutes) and on having jobs that are at least a bit flexible as to time-shifting.