Get full meteorite armor and space gun. It is super good since that when you have the full set, the space gun costs 0 mana. But i used this somewhat good technique with the Water Bolt. I just had a water bolt, flying boots,mana potions, and lava charm. I shooted the water bolt in the roof because it can bounce back and hit the 3 segments of the boss, and it worked
I beat him with Hellstone armor, Fiery Greatsword(A.K.A Fire Flame Flow Sword), a landbridge, campfires the whole way across the world, and some Heart Lanterns. The landbridge is also good for the hardmode bosses (If you raise the roof of the Underworld a little)!