When I played all of my Pokemon games, my Togepi evolved fully from being happy by doing these things: Constantly taking him/her with me to every fight, feeding her waters and berries, giving him the ability to at least use a move like flash or fight in a battle every now and then, and don't let it faint too much.
In Pokemon Diamond or Pearl, you have to first beat the Elite Four. Then go to Route 230. Use a Poke Radar there and a Togepi will appear. In Pokemon Platinum, you will get a Togepi egg from Cynthia in Eterna City. For more information, go to: http://pokemon.marriland.com/diamond_pearl/pokedex/togepi/
You can have a Togepi with the move metronome. Or, you can buy the furniture metronome underground. (These are Pokemon that have metronome too.Cleffa,Clefairy,Clefable,Togetic,Togekiss, and more).
Togepi evolves when it's happiness value is at 220 or higher when you level it up. you can raise it's happiness value by winning battles and giving it items, and gaining expert points, and keeping it in your party. Also, don't let togepi faint.Read more: How_do_you_make_togepi_evolve_in_Pokemon_platinum
certain pokeblocks can make Pokemon happier if your talking about Pokemon emerald or Sapphire, but generally the more you raise your Pokemon the happier they become.
if your Pokemon level ups, its happiness will increase automatically. but if you give your Pokemon a soothe bell, its happiness will increase faster, and it will evolve faster (by certain Pokemon). also return will do more damage
Platinum
You don't need an Action Replay!You can get a shiny togetic by chaining a togepi to shiny.Evolve Togepi by get its Happyness/Friendship to max! :)u guys are retards catch regular togepi and evolve it by making really happy with u then evolve togetic with a shiny stone who ever likes shiny Pokemon is a retard shiny Pokemon are bull crap
Whenever the togepi completely likes you it can evolve around level 20. TRICK: Use protein, iron, carbos, zinc, calcium to make togepi like you more.
Pokemon Platinum because you can catch more legendaries!
there is no more masterballs in Pokemon platinum but not if you use cheats
There isn't a Rayquaza in Pokemon Platinum. For more information contact me at likefruit89@yahoo.com.
i reckon PLatinum. it has all the new features but doesnt allow some Pokemon to appear in the wild that do in Diamond/ pearl. but platinum also has even rarer Pokemon that don't appear in pearl/diamond. I have all three. YAY