Honestly this is how I train all my dogs.Baby puppy? Train when they are alert and looking for mischief. Training sessions should only be a couple of minutes (five at the most), spread out over oh... upwards of a dozen times a day. Either set a timer or grab a few treats and train until they are gone, and then move on, so that you don't melt their brain by going too long.
The youngest is 2.
Short with a handful of treats works well.