Avoid weed and feed and other herbicides. Children and pets are especially vulnerable to chemical exposures, and lawn chemicals find their way into rivers through storm drains. Weed and feed is also wasteful since it broadcasts herbicides over the whole lawn even where there are no weeds.
Your lawn doesn't need to be entirely weed-free. If you feel the need to weed, do it by hand using any weeding tool you like. A hori hori knife or dandelion tool makes short work of deep-rooted weeds. If you have too many weeds for this, consider hiring a neighborhood kid to get it done for you, or focus on problem areas instead of trying to get every single one.
Don't rip and run! Get weeds out by the root and then overseed the spot so grass wins the fight. Try mixing the seed with some potting soil for your own "divit mix" like the pros use at the golf course. Make sure to keep the new seeds evenly moist to ensure germination.
If you do use an herbicide, spot spraying is always better than broadcast application.