Food:
More sources of food, like banana trees and berry bushes.
Fishing boats for bigger catches. (requires a high engineering level)
Fishing nets for bigger catches. (requires something to get)
More then one field.
Upgraded agriculture tech will give bigger harvests.


Seasons:
As some have suggested before day and night would be nice but wouldn't "fit" with the time line. But seasons would. It would make things look a bit better but more important you can time different things to different seasons. Like crops and events of cultural significance. Like a party every equinox. Or that some task have to be done at a certain season. Also things like the flu (several people sick) could follow seasons.

Hope I managed to give you a few good suggestions.