Are you planning a play date? Wondering how many kids to invite? How long to have it? If you should serve a snack? Here are some guidelines from Parents.com:

Play dates are a great way for kids to work on building their relationships, but it's important to keep a few things in mind when planning one, according to Tovah Klein, PhD, director of the Barnard Center for Toddler Development in New York City:

1. Three's a crowd. Toddlers do best in pairs, notes Dr. Klein. They don't interact as threesomes or foursomes, so it's easier to invite one child at a time.

2. Less is more. One hour is a good length for a play date for kids under 2. If you sense your child is miserable -- if he's tired, overwhelmed, or not feeling well -- end it early.

3. Keep it friendly. Make the play date with someone your child likes, not someone who happens to be convenient, such as your best friend's daughter.

4. Take a snack break. When kids run out of steam or get too wild, shift gears by offering a healthy snack of fruit or cheese.

5. Plan ahead. To cut down on toy disputes, think of projects that encourage side-by-side play, such as racing toy cars, running through a sprinkler, or drawing with sidewalk chalk.

6. Don't overdo it. If your child is more aggressive than usual, cries, or doesn't seem happy to have a play date, he may be saying, "This is too much for me." We tend to think kids are better off with lots of friends, but they really don't need to be with other kids all the time.