1. Redirect. If your preschooler is jumping on the couch or grabbing a toy away from his sister, distract him by asking if he'd like to read a book together or draw a picture.
2. Prevent meltdowns at goodbyes. If your child is nervous about spending time apart, give her something to remind her of you. Give her a tissue that you kissed or a picture of you and put it in her pocket. Having something physical to touch may help her feel less anxious and help prevent a meltdown while you are gone.
3. Involve him in righting his wrongs. If he knocks over his brother's block tower, ask him to help rebuild it.
4. Don't delay discipline. If you have to discipline your child, do it when you see her misbehaving. Cancelling a trip to the zoo on Saturday because of a tantrum on Thursday won't prevent future outbursts. It will just feel like random, undeserved punishment for your preschooler.
Source: Lamb, Marguerite. "20 Tips for Parents from Preschool Teachers." Parents.