Hi S. ... my daughter Cameron is almost two ... and at 15 months I had no idea if "time out" would work, but it did. My husband and I had to be a united front on this, because it would take several tries to get her to understand. She will cry, she will scream, she will throw a fit ... but you and your husband are the boss and are her ultimate security blanket.
She is getting to an age where she will test and test and test ... Cameron is now starting to get even more excited when she starts acting up, so you have to get it under control now. We started with a warning ... then if she continued we asked her if she needed to go to "time out" ... she couldn't talk that much, but she did have a reaction in her face ... and finally when she did it again, we walked her over to the corner (ours is actually a wall in our foyer where she can't see either television or the activities going on in our living room or dining room, and we stood next to her .. when she would try to turn or walk away we would tell her to face the wall (each time getting a little more stern in our voice (she has to know clearly what is expected of her). We would have her stand there for a minute (one min per year of her age)... then we would walk her over to her chair (her favorite place to sit) and tell her how much we love her and what she did wrong that made this "time out" occur.
Simple instructions and explanations (they don't "get it" if you talk and talk and talk). We would kiss her again and tell her how much we love her ... and then whatever she hit or did to the dog or us, she would have to go and apologize to the dog or us. Little one like that don't understand empathy, so they are very passionate.
It also helps to teach her the "sign" for sorry ... and the "sign" for please and thank you ... it gives them a sense of responsibility.
One last thing ... have her stand and not sit when you do time out ... it's a little more uncomfortable so that they stay focused on what you want them to do ... and stand with them so that they know you are serious and that you will stop what you are doing in order to take care of this. I hope this helps ... I am 38 and a mother of two little girls Cameron (age 2 - Cancer) and Samantha who is 4 months old ... I was that little Aries growing up and the teachers I appreciated most were the ones that were strong! Be that teacher ... your daughter will thank you for it in the long run ...
My daughter is about to go to daycare at the YMCA one day a week ... they are treated like preschoolers, and they are only with kids that are the same age as them, in groups of 7 ... this guideline for time out I have described is also what they use ... I actually had to have my daughter have a time out at a clothing store the other day ... she thought that just because we weren't at home that there wouldn't be a wall to stand at ... she will never act up like that again. All the mommies in the store "got it" and understood. I was surprised at my strength to be willing to be embarrassed ... I thought of it this way ... "I didn't have to yell, and I don't spake my child" -- and we ended up with some tears and I great "Sary" (sorry) and a hug. She still loves me and I adore her and her spirit. You can do this ... you are a great mother ... don't give up!!!