We have this puzzle that I absolutely adore for beginner puzzle users - aka Becca right now. All of the pieces are the same size and shape so you can practice just putting them in the puzzle without having to also figure out which piece goes where. Becca has been playing with it for a couple of weeks now and I was just thinking the other day that I should probably introduce her to the concept that each piece also has a correct spot and see if she can start matching up some of the animals.
She came to me the other day with one of the pieces in her hand, babbling on about something and trying to get me to follow her. I asked her if she needed help and she said she did, so I followed her to find this:
She had matched up all the animals (OK, their heads were all upside down but still) and was stumped by the last two - I assume because they are both brown. So either I simply have a very brilliant girl or she has been tutored in the "right" way to do the puzzle by her brothers. Probably both.