I teach 2-3 year olds. What I do, is I have a small child's chair in the corner. It is red. All of the rest of the chairs are blue. The red chair is the time out chair and I just sit them in the chair for at least 2 minutes at most 5. It depends on their age and what they did. They know that the red chair is the time out chair. In fact one time I had a parent sit in it to help his daughter get her things and one child went up to him and said, "you can't sit in the red chair that is for time out and you didn't do anything wrong." I thought it was cute ..:)
I do use the supper nanny technique in that I do explain to the child what they did and why I am putting them in time out. When they are finished, I ask them why they are in time out (if they need help remembering, I help them) and they tell me, then I have them apologize to me, or to the person that they offended.
I would put the whatever you are doing, chair, rug, I have heard some people using a cardboard box for them to sit in. In a place where they cannot play. The bedroom is a bad idea, because a bedroom is where they play and sleep, not where they go when they get in trouble.
I usually have no problems with having the child sit in the chair, if they get up, I just pick them up and put them right back in the chair again, and start the clock over again. Children are smart, they will understand that if they keep getting up they will get put back in. Sometimes they cry, I have had children scream, but when all said and done they end up being much better children when they get out of time out. I have been teaching for three years and I rarely ever have problems with my children in the classroom. I have up to 10 2-3 year olds at one time.
Consistency is the key with any discipline. If you are not consistent the child will get confused and test your limits and neither one of you will be happy.
Good luck...:)