I'm sure you'll get good ideas from others, but I have to say grounding never worked for us. It turned into punishment for me, because she made life intolerable while she was grounded. My mom's default punishment was grounding me, and it didn't do anything to change my obnoxious behaviors, but it did make me resentful, hateful, and very sneaky.
When my dd was a toddler, she frequently told me I needed to go to time out. :lol: Sometimes she was right.