I have 2 daughters too. 4 yo and 2yo. I spend the most amount of time with the older when other one is napping in the middle of the day. We also have activities that center around each. While older is in school, me and little one have music class once a week. While I'm with both, older one has a dance class and we watch.
My husband takes the older one out on a date every once in awhile and me and little one have a night to ourselves.

It's hard juggling but it's better than being an only child, in my opinion :)