[yorkietalkjilly]

Just start back over and do only the one trick - sit. Get down on the floor with her for each training session and just stop her when she starts to roll over and gently help her go back into her sit and praise, praise, praise with your best baby-voice when she assumes that position. Since she is an anticipator, this may take some time so be prepared to interrupt her attempt to leave the sit and go into the rollover with very gentle hands, gently helping her back into her sit. She will soon begin to anticipate that you are going to interrupt her attempts to rollover and stop trying it. Stay with just that one trick until she stops trying to roll over at all, even when you are not on the floor with her. Teach her the "wait" so she can learn to sit and then wait in the sit until released. This will reinforce the idea in her mind that for now you want her to remain in her positions until released by whatever word you like.

Then go to a completely different trick and watch her very very closely so that she doesn't try to start anticipating/combining with anticipation and just gently interfere if she does. Sometimes training is a real hands-on business but any handling should be very gentle and extremely positive just so your Yorkie gets the idea Mommie is using those hands to gently guide her into what she should be doing. Soon she will get the idea that she should hold the end of her trick until her release word and then can go on to whatever is next.

Many dogs that love tricks get into anticipation and it is up to us to patiently show them that is not what we want and guide them into what we do want. Positive reinforcement of guiding hands is often necessary with eager dogs so they don't get into "bad" habits of combining tricks or leaving a trick too soon.