Here we go :
When your tama beeps and the attention light is on (the icon on the bottom of the screen farthest to the right)
1) if the tama is crying or in a bad mood with its back to you -> PRAISE IT
OR
2) if the tama looks like it normally does and doesn't have ALLl its happy and hungry hearts gone -> PUNISH IT. This will lower your happy meter by 1 heart quite often - so i always fill up the happy and hungry hearts first, then punish, then check the happy hearts.
doing this will ALWAYS increase your training bars.
punishing a tama for giving a bad present, or refusing food or refusing to play a game will not increase the training bars, although it does say in the instructions, to increase discipline you should punish the tama if it gives a bad gift - so i usually do that - but i don't know if it does anything really.
//Haze