Come prepared Bring along several toys so your child has a home base of pails, scoops, and sifters. The more fun stuff she has, the less likely she'll be to grab another kid's things.
Be generous When a child eyes your toddler's toys, offer them up with a smile. Sharing doesn't come naturally to young kids, "but when they see their parents cooperating, it can rub off on them," says Anastasia Galanopoulos, Ph.D., an assistant professor of human development at Wheelock College, in Boston. Try to get the pair to work on something together, such as putting sand in a bucket and dumping it out again. Then your toddler will be more likely to forget that an interloper is using her things.
Practice park etiquette If your child can't resist playing with "abandoned" playthings -- no owner in sight -- let her. But if the newly discovered treasures clearly belong to another child, ask the other parent if it's all right. The answer will almost always be yes, but you'll score points for checking.
When she's tired of using the toy, be sure to say thank you. If the other child decides he's got to have it back before your little one is finished, you'll have to come up with a clever way to get it out of her hands. Your best bet: Distract her with one of her own toys or a new activity.
Keep watch If another child is playing rough and his chaperone doesn't intervene, tell him calmly but firmly, "No hitting" or "No pushing." Kids usually stop when a stranger reprimands them. If the bad behavior continues, and his caretaker still doesn't step in, pick up and move to another part of the park.
Bait and switch When your child is hogging a piece of equipment, such as the swing, try to lure her away with a fun alternative. If she resists, physically remove her anyway and say, "Someone else wants to use the swing now, and we have to share." She may get upset, but she'll recover as soon as you get her involved in something else.
Secure your snacks Keep your food and drinks out of sight in closed containers to discourage other kids from helping themselves. If you do offer some goodies, first ask the other parent if it's okay. And follow the golden rule: Make sure your tot doesn't raid someone else's unattended crackers and juice either.