If you want to increase the amount of bars that are in the training meter you have to look at the attention icon and check if it it is beeping or flashing. Now you need to do the right thing in order to increase the training meter. If it has its back turned to you or it is crying you need to go to the discipline screen and praise it to make it feel better.(the Pacman shaped icon)If the attention icon is beeping or flashing and your tamagotchi is acting as usual than you need to go back to the discipline screen and give it a time out because it has called for you for no reason. By doing each of these things you gain one training bar. Your tamagotchi probably doesn't have a mate yet because you have paused it or paused it unknowingly. If you have another tamagotchi that is able to mate with it than that is your best bet.Hope this helps and sorry if it is too long.
you can increase the meter if you disipline it when it calls but it needs nothing, and praise it if its crying or looks angry. to get a match you may need more skill points.
If it does not meet a compatible mate or find a mate, when it ages to around age 9-11 it will change to a oldie and you will have to find male/female oldie to mate with or the tamagotchi will pass away!