i think i caught my mewtwo w/ an ultra ball. i think had:
-charizard lv 50-something to 60-something
flamethrower
heat wave
fly/wing attack
???
-vaporeon lv 60-something
surf
aurora beam
blizzard
dig
-articuno lv 50-something
ice beam
fly
secret power
hyper beam
and i cant remember what else i had way back then, it was too long ago. like near christmas. but most of the time when i catch a legendary, i save before i battle, i battle, i die, i turn it off, on, battle, kill it, off, on, kill it, off 4 a while, on, battle, kill it, off, on, battle, kill it, off, on, ultra ball at beginning of battle, catch it. and during the whole process im really mad at the stupid game. it usually works! but not all the time. try it. save, battle lots of times, turn off if something bad happens, like if ur really fustrated or someone dies, keep it off for a few minutes or until u calm down, turn on, ultra ball. something like that.