When my two year old misbehaves I have found that putting her in time out and letting her decide when to come out can be more effective that leaving her in her room and then telling her when she can come out.

My daughter is very independant and wants to make as many of her own decisions as possible. Giving her the opportunity to make the decision to leave time out makes it her responsibility to follow the guidelines that we set.

For example if she throws a toy at her little sister, she goes into her room. She will calm down and then come out on her own. Usually she apologizes to her sister and gives her hugs and kisses but if she throws a toy again or does something else that is unacceptable she goes right back into her room.

I also find it important to make it clear to children what is ok and what is not ok and to be consistent in following through on consequenses.