train up in a place that is weak to the Pokemon you are training up and you should run into it.
The only way to obtain a Latias in Pokemon Diamond is to have it migrated. Latias is not a Pokemon that is encountered naturally in that particular game. The only game that does have Latias is Sapphire version (which can trade to other games, respectively). Thus, to have a Latias in your game, you must either use a cheat code or migrate it and re-capture it in the Pal Park.
There is no secret or hidden trick to finding Latias or Latios. Well you can use a Action Replay or a Game Shark but I'm talking about not cheating. You find him randomly. I was playing Saphire trying to Find the Regi Pokemon while I was surfing, and i got into a wild Pokemon battle with Latias without even trying to find him. So the best way to find him is to not try to find him.
you don't. there is no way to get latios OR latias in d/p. You can migrated it from earlier games though...
It can be found anywhere an easy way to track it is have a friend trade you latias so you can receive data on it check your pokedex to find it use the masterball on it and your done.
You can find Latias in Soulsilver throughout the Kanto region.
You can find Latias and latios anywhere in Hoenn. You just have to get lucky.
Once you become Pokemon champion latias appears but it roams Hoenn making it difficult to find try to stay around 2 different routes that way you make it somewhat easier to find you can find it in the grass or the water either way you need to look hard.
You can find latias on every route in hoenn.
Latias is not available in SoulSilver
The only way you can tell latias is in the area your in is if you seen it before and you use the pokedex to search latias.
latias
trade it