ok for this u will need:
a bunch of fusion monsters
1 Magical Scientist and
1 Cannon Soldier.

get Magical Scientist and Cannon Soldier on the field. activate Magical Scientist's special effect to sp. summon a fusion monster to the field. then use cannon soldier to launch it at ur opponent's LP. repeat until either ur fusion deck runs out or ur opponent's LP reaches 0.

it's kinda old, but if u have good fusion monsters, it works wonders. :)

kinda old? this was invented when MFC came out O.o
thanks anywho