Ugh, this has been on my mind for a little while. How do you discipline a two year old? I don't have the answers, but I can speak from our experience what has been working in our family. It's an ever changing process with Hunter. I am a big fan of changing up how you deal with things based on what works or is working at the time for your child.
A firm "no" was the first thing that we started with Hunter, about a year ago. At the time it worked well and he could tell we did not approve of his actions and would stop. After he got a bit more stubborn, that changed, he would just look at us, as if saying "Really, you think that's going to stop me?!".
So, we started using timeouts. Oh, they were my best friend for several months. Hunter would hang his head in time out and then rush over to me to apologize. We would hug and then talk about why he went to timeout. I got to the point where I wasn't physically putting him in time out, I would just tell him to go to timeout and he would. Oh those were the days!! After a couple months, nope, not working anymore. He would just sit there with no remorse and think nothing of it and then go back and do whatever had gotten him into timeout five minutes before.
So, we switched to spankings. Go ahead and judge me, that's fine. But I do believe in spankings. I've never done it out of anger nor have I actually physically caused harm to my child. Jesse even teases me that I have never really given him a "spanking" just a tap on a diaper covered bottom. Whatever. It worked. It would shock him a little at first and then it hurt his feelings. His bottom lip would stick out and he would say he was sorry. In the last month... nope no reaction, just a stare down.
So... that leads me to where we are at right now. We have moved on to taking things away for bad behavior. He hits the puppy, he gets a toy or the TV taken away. He doesn't clean up his toys when I ask them to, he's not going to get to use them for the afternoon. This has been working like a charm. I think it's just a natural progression with age, what "hurts" them the most at the time. Right now, the thought of not being able to watch the rest of Octonauts sends him into complete panic and he rushes to correct his behavior.
Call me crazy, but I like the discipline aspect of parenting. I know that it turns me into a "bad guy" at the moment, but it shaping him for the future. It's offering him guidance into becoming the man that God wants him to be. So yeah, when I see progress in his actions, words, and affection towards other, I like being the primary one to guide him. There is not doubt in my mind that being willing to discipline your child is an act of service and love for them. I love my son enough to want to mold and guide him to greatness.