Hi H.,
I own a home-based childcare and just this week, had to put a little one in time-out for the very first time. She is 15 months old and likes to pull hair. On the first one, she went in, came out, I guided her back to the corner, she came out, etc...it took 8 tries. She finally stayed there for one minute or so and for the rest of the day, she would go to pull hair, look at me with hand poised above the "victims" head and pull her hand back. I would tell her "Good girl! We don't pull hair, pulling hair hurts!" and give her a big hug. She had one more time-out this week, which only lasted a minute because she stayed in time-out right off the bat. They learn very quickly what they can and can't do. It just takes practice.
Remember to gently guide her back to the corner, using the same words over and over..."we don't pull hair, go the the corner." After the third time of guiding, don't use any words, just guide. After the time-out, always talk to her about what she did and that it's a no-no. Follow up with an apology to the victim and then a hug and kiss and a "now go play." They understand so much more than we give them credit for! I also used "pre-teaching" throughout the day. What that means is, I would stop her from playing, call her over, get eye to eye with her and tell her "we don't pull hair, pulling hair hurts! We don't pull hair", then I would give her a hug and a kiss and send her back to play.
I have used this technique for years and it is very effective when used consistently. We rarely have time-outs in my childcare and I usually have 8 children that I care for daily.
Good luck!
C.