ps for the older students you can explain a bit more about dynamics in phrasing, and also cut the "1/2 principle" down to simply making sure you have an eighth rest before the next phrase. Starting with a little more time, gives them opportunity to look at what is coming next.
Sightreading is another technique that sometimes teachers overlook teaching. I think, personally, it is the idea of looking ahead (at first) WHENEVER YOU COME TO A HALF NOTE OR WHOLE NOTE. You've already found the note--keep looking forward and don't wait until the last minute to know where to go.
Smoothness in playing is another technique. I was just reading another posting about a 42 year old student. Eliminating unnecessary movements is VERY important, i think, from the beginning. Sometimes you will see children who think they are too short, scooting on the bench to play something higher or lower. I always say lean this way or that, but DON't scoot. Let arms hang naturally from sides, and let hand be relaxed.
Using the metranome in playing pieces DOES help with the smoothness idea. You can take the time out of a measure (as mentioned above) but should not practice a lot of rubato technique until later. (ie adding time to the phrases) Playing in strictness of time