When your Tamagotchi calls for attention and it is crying, praise it. If your Tamagotchi calls for attention and it does not need anything (it does not have all empty hunger or happiness hearts), give it a time out. But you probably already knew that.
If you have another Tamagotchi of the same version, you can wrap a food or item and send it to the other Tamagotchi via the "present" feature (but it has to be with the SAME version). After you wrap the object in the "present" section under the 9th icon, you can send the food or item to the other Tamagotchi.
When the other Tamagotchi unwraps it, it may be what you intended to send, or it may be something else, such as a snake or jack-in-the-box. If your Tamagotchi did not send what you meant to send, the other Tamagotchi will be very upset and your Tamagotchi will be sitting on the screen with a really weird expression on its face. Give it a time-out and you will get a training point.
If your Tamagotchi did not send a bad gift, wrap another gift and try again.
You have to wrap gifts yourself for this, you can't just select "present" when connecting and let it send any gift. You have to determine what gift it is supposed to send and discipline your Tamagotchi if it sends the wrong gift.
Hope this helps! Trust me, this process is easier done than said...