Pokémon Mystery Dungeon: Explorers of Sky Tips

Legendary Pokemons recruit
The best way of getting pokemons is to know where they hide first.
(They as listen in Dungeon pokemon Guide/FAQ)

Then you get a golden Mask/Friend bow
(Golden mask is VERY hard to get - North zero isle -75 floors)

Friend bow should be possibly aquirable through a wonder-mail s.

When you reach the legendary pokemon you want (Some are rare and hard like darkai or easy ones like palkia,which is 100% recruit success rate)

You must finnish the legendary with the pokemon that hold the item and if your lucky,hes gonna join your team!

Watchout to turn off all moves of partner when the pokemon is low,you can also (If you are good) go as solo to beat him.

Another hint: use recruitment search, it is really useful
Hope it help.