When you go to the Tama log icon (the book) just simply go to the friend icon there and hot The "B button", then go to tthe friend you are mating with to check the level of your friendship...or love with that Tama. By going through the list by pressing the "A button" and hitting "B" untill the smilie faces or hearts appear.
When you visit a friends house (On Tama) by giving presents or visitng you will increase the meter.
And playing games is also a good way to do that too.
eVentually after Time your Tama will begin to kisss the Tama when viisting or giving a present..