3rd Gen finding Latios (Emerald)

How can I go about finding Latios after I talk to my mother in Emerald? I read a Faq and it pretty much said I can only find it by getting lucky running through grass... Is there a better way? Note that he is not on my Pokedex yet so I can't track him down that way.

i wrote this a wile ago in another thread i hope this helps

"well what i do to catch run away legendarys is save on a route where they can be encountered then walk around for a wile and if it does not come out i turn the game off then on and walk around again (in the same route)and i do that till i encounter it if you see it and it runs off this would be easier since the pokedex tells you what route its currently on"