Use craft time to model how to share.
For this craft, all you'll need is a piece of paper and some stickers.
Cut the paper into any shape, or leave it as is. Divide the stickers into two piles, and tell your child that you're going to take turns putting the stickers on the paper.
There are so many fun ways you can adapt this craft, too. Try paint, foam shapes, tiny pieces of ripped paper, etc.