Question

for example A then B repeteadly? or down on the pad and the B and A? (one example i've readed says: that rayquaza is easiest to catch if you press down on the pad and when the pokeball opens hold B)

Answer 1

No. Each Pokemon has a " Catch Rate ". Legendary pokemon have a higher catch rate. Unfortunately no because I used to do that and I know it is just a coincedence.