Oh for the good old days when the kids roamed free in their neighborhoods! Now, instead of socializing on the corner, children visit during "playdates," having friends over at appointed hours.

The good news about playdates is that they help kids learn to get along. When the playdate goes well, mom and dad can also get a break as the children entertain themselves. It's delightful to see your little one share her favorite toys with a friend. And these get-togethers are a nice way to connect with other parents.

The bad news is that playdates can turn ugly in the time it takes to say, "That's mine!" With a few faux pas, it's also easy to alienate the parents of the small guest who attends the same school as your child.

As a mother who has hosted playdates successful and not so stellar, I pass on these tips to make your little meeting a happy one.

*Let your child pick her friends. With toddlers, playdates are about getting the parents together, so it makes sense to target kids whose folks you like. When children can be dropped off, however, it's best to consult them on playdate picks.

*Avoid threesomes. Two's company, three's a crowd was never truer than with small fry. Unless all is going well, try to distract little sister with a separate project or even a movie. Better yet, get her a playdate.

*Invite the parent in. Your little visitor may dash in the door and not look back. But if the playdate is a first, his mom or dad will appreciate getting a lay of the land. Show the other parent around.

*Note the info. Get the contact number and ask whether your guest has any food allergies or special issues. Also, set a pickup time, making the playdate short and sweet, say around 2 hours long. Ask permission if you want to do something unusual, like take the kids swimming.

*Corral the guest's stuff. There's nothing worse than racing around to search for missing shoes while the other mother waits at your door, car running, toddler crying in the back seat. Put the friend's things aside early on.

*Set Rules. Tell the kids what they can and cannot do, but keep the list short. In our house there's no playing in mom and dad's room and no jumping on beds.

*Butt Out. When children are under four, you'll have to supervise and manage them closely. But let older kids play independently and come up with their own fun. Check in often, though. Silence is not necessarily golden. It may just mean that the bathroom mirror is being colored with your new lipstick.

*Feed them. Popcorn, pretzels and fruit have resuscitated many an ailing playdate at our house. Low blood sugar makes for lousy relations.

*Prepare for Revolt. Your guest may act well while your own child undergoes a Jekyll-Hyde transformation. Kids like to test their powers when entertaining on home turf. Let your child stew, and engage the friend in a game. Your kid will eventually join in.

*End on a high note. Children may argue for most of the playdate but if it ends while they're having fun, that's what they'll remember. Rescue a flagging playdate by doing something silly, like making a yucky potion out of toothpaste, ketchup, vinegar and baking soda.

*Don't trade belongings. Especially early on, kids want to take toys home from other houses. I've played this game. It's a no-win. No sooner has one child agreed to give away her precious bear, than she changes her mind and bursts into tears. Save yourself grief and ban these little exchanges.

*Tell all. Okay, so the playdate was a disaster. Her daughter broke your child's favorite toy and then walked in on your husband while he was getting dressed. Let the other parent know what happened. It's better for her to hear the straight, bad version from you than a horrifying, inaccurate one.

*Take her up on it. The other mother picks up her child, thanks you and says she'd love to have yours over. Really? When? Set a date to keep the playdate ball rolling. It's great when you can take turns hosting.

*But don't expect reciprocity. Be understanding if the other parent doesn't offer to host the next playdate. These get-togethers don't fit well into many families schedules. Don't take it personally. Parents' lives are so busy these days that they often don't have time to date each other.

*Opt out. Guess what? Playdates are optional. Kids can develop social skills in all sorts of other environments. And if they play at the park, you don't have to clean up afterwards!

Jennifer Bingham Hull's award-winning book, Beyond One: Growing a Family and Getting a Life, looks at life after the second child. www.growingafamily.com