User blog comment:Levi de koning/hardmode/@comment-4816368-20130802170048

Build a new base deep in the Jungle. You won't have to worry as much about the corruption (as long as you defend it right.)

Once you've got that, go to the corruption that was spawned when the world was made, not when Hardmode started, and quickly smash at least 1 demon altar with the Pwnhammer (more if you can do it without getting killed, as more is much better)

Once you smash enough, you should find Cobalt underground. This is the first stage of Hardmode progression. Get some Cobalt with a Moletn Pickaxe to make at least a Cobalt Drill and a Cobalt Sword (60 ore pieces)

If you haven't blessed your world with Mythril yet, do so now.

Use the Cobalt Drill to get some Mythril, and then craft a new anvil out of it and afterwards, craft armor and a drill out of it (but not weapons)

Make sure you use a Mythril Helmet (not hood or hat) for maximum defense.

By now, you should be strong enough to smash many demon altars without getting killed.

Once you break lots of demon altars, make Spelunker Potions and go down to where you start to see lava, but not in the Underworld.

From there, use a spelunker potion and look for what looks like red copper. Mine that, because it's Adamantite.

Once you get 30 adamantite ore, craft it with your Hellforge to make the Adamantite Forge.

Now you can make things with Adamantite.

Once you have full Adamantite Armor with the Helmet, you are ready to start exploring the Underground Hallow and Underground Corruption to get souls of Night and Light safely.

For fighting the new bosses (not counting the destroyer) make a skybridge with a house in the middle. Make the nurse move into the house, and set your spawn in it. Keep a magic mirror in your inventory when you fight so you can warp back. Once you do this, just summon the boss and fight it with the Clockwork Assault Rifle, or the Megashark. Fight the destroyer first, on the ground. You can make the megashark once you kill him, so make sure you have that.