Unfortunately, there is one thing that I do not know; I've broken all the crimson orbs I can find, I have a full set of Crimson armor and tools, but I don't know what to do next. I've beaten Skeletron, the eye of Cthuhulu, the brain of Cthuhulu, Goblin Army. I've maxed out my health, and I have quite a few useful offhand items.
Next, you'll need to kill the Wall of Flesh in the Underworld. Kill a Voodoo Demon to take its Guide Voodoo Doll. When you're ready, cast it into the lava to kill your guide and summon the Wall. My favorite strategy is to use a full set of Meteor Armor and the Space Gun, as the Meteor Armor's set bonus is unlimited ammo for the Space Gun. You'll need a large platform and if you really want to ensure victory, make a house with a bed in the exact center of the world and set your spawn there, in case you die, so you can run back down the platform and keep the fight going. Good luck!