We came up with a great way to keep the sharing fair. If we had candy bar that I want two of the kids to share "fairly and equally". I let one of them break the candy bar in two and the other child picked which half they wanted. Suddenly my kids became EXPERTS at breaking off or cutting equal parts of any treat. After having done this for most of their lives, I would actually catch the "choosing which half" child take the portion that perhaps wasn't quite half, knowing that their sister had tried. Especially if the dividing sibling was younger and they knew they had done their best. This in itself taught yet another lesson to the younger when they would see the other sibling not immediately go for the piece that broke off slightly larger. :) I actually enjoyed watching this ritual transpire and could see just how they changed and developed as they got older. No more fighting over who got the bigger portion.