I read a fantastic blog post a couple of months ago by a male preschool teacher called Teacher Tom. The post was specifically about scattering; a phase that many 1-2 year olds go though that is characterized by the need to dump out and scatter anything that is organized. Many kids are messy and that goes well beyond age two. Scattering is more specific though. For example: seeing a box of blocks, dumping the box out, and moving on. K was all over this scattering business and it was exhausting. Every day I floated between picking up after him and fighting with him to pick up after himself. I refused to simply keep everything out of his reach, I wasn't going to lose the whole lower three feet of my house to my two year old.
Since then I learned that this technique works very well on K and not just for scattering.
Now when K takes a toy from his sister H, I simply inform him of the problem without placing blame on him. I tell him that H doesn't have anything to play with and ask him "what should we do?" Immediately he either gives H the toy back or fetches her a different one for her to play with.
Of course this technique does not work all the time. Some situations where his safety is important he needs to hear NO or STOP. Other times when he is in a really bad mood he just needs to be taken out of the situation. Generally however, it has been a wonderful tool that has considerably decreased the amount of fighting I do with my two year old and I am forever thankful that I came across that blog post.