If it's night, use a dusk, and if asleep use Aultra ball or heal. If you want to take a good risk use a poke ball. All 3 are really great at catching Rakou. I even caught Red Gyarados, Moltrace and Entei with one.
Ultra balls
A Masterball.
U have 2 trade him
Pokeballs are your best bet
use your best pokemon and pokeballs
Web Caching
MasterBall is the best UltraBall is next GreatBall is next Pokeball is next
you have the best chance of finding and catching raikou(or any of the legendary dogs) on route 1.(use your master ball. raikou can run away.)
No, raikou cannot be evolved, because he's a legendary pokemon.
Pokeballs are basic and arent that great at catching pokemon. Greatballs are slightly better. Ultra are the best quality to catch pokemon. Masterballs no matter what will catch the pokemon.
Caching
Get the best pokeballs and go search for it.