I just reached Hard Mode in Terraria after beating the Wall of Flesh, so what do i have to do next? I know that to call the new bosses you need to create an specific item. But regarding the ore grinding and armor sets and weapons, What should i get?
You need to start breaking Demon or Crimson Altars with the Pwnhammer. This will spawn three new tiers of ores that you need to mine. The ore you get is determined at random when you smash an altar. The ores are: Cobalt/Palladium, Mithril/Orichalcum, and Adamantite/Titanium. Each altar smashed will spawn some of the next ore in the list, starting at the few new tier. The first spawns Cobalt (or Palladium), the second Mithril or Orichalcum, the third Adamantite or Titanium, then fourth circles back around (Cobalt or Palladium). After each ore is spawned once successive altar smashes will produce less and less of that ore. And each alter smashed will spawn a block of Corruption, Crimson or Hallow somewhere in the world which will contribute to the spread of those biomes. I have heard it suggested that the new ores are more likely to spawn in the underground jungle, but I cannot verify this from my own experience.
Now, I personally like to aim for Excalibur and the Megashark first. That's because you need souls of Might - dropped by Destroyer - to make them. I find him the easiest Hardmode boss to tackle. Because of that, I don't build a lot of hardmode gear (except armor). I only need the swords (I go back and build other stuff later of course). But before I worry about swords or armor, I go for the drills.
It looks something like this:
Mine enough cobalt for a drill then mirror out and make it.
Return to mine for Mithril. Mine enough for the Anvil and a Drill, then mirror out and make those. I will mine cobalt during this trip down, and if I have enough spare I will make a sword (since you can hold it down and swing it, a property the Mithril and Adamantite swords do not share), then armor pieces.
Return and mine for Adamantite and Mithril primarily. Make Adamantite Forge, then drill (though this is not strictly speaking necessary, but it is an upgrade), then make Adamantite armor. Then make Adamantite sword. I will use Mithril armor as a stop gap until I get a full adamantite set.
During this process, you want to farm crystals when you can (if you plan on using guns at all; crystal ammo is amazing) and get as many souls of light/night as possible (can drop from any enemy killed in the underground Hallow/Corruption). Those souls are the gateway item for summoning the new bosses.
Once I can summon the Destroyer, I get a weapon to kill it with. Typically that's a Phasesaber. I make Excalibur (which really speeds up farming him) then I make the Megashark (which I use for the Twins and Skeletron Prime).
My way is not the "best" way, but I find the Destroyer easiest and I rather like those two weapons.Bow lovers can easily substitute repeaters for this process, and you can kill the Destroyer for a Megashark or just try to farm the twins (for the Hallowed Repeater) first. Magic lovers want to forge Crystal Storm.
There are a lot of options. My general advice is not to stop and build a full set of armor/gear at each new metal tier. Build as little as you need to progress to the mining of the next tier. If you are dying a lot, then alter tactics (and if need be, do stop and make some better armor).
Once you kill all of the Mechanical Bosses, the Hard Mode Jungle awaits!
Go make traps and purify the corruption. Keep seeds handy, and try to control the hallow enough so it will not spread. Smash some demon altars, checking for corruption. If there is any that you see, purify it. Go mine enough cobalt for a sword, a full set of armor, and 80 extra. Do the same with mythrill, and then with adamantite. Once you have a full set of adamanite armor and a sword focus on getting greater healing potions. If you like ranged damage, try to get a repeater, megashark, or shotgun. Try to get cursed bullets or high tier arrows for ammo. If you prefer magic damage, get a crystal storm or golden shower. For people who like flails, go for Dao of Pow. I personally think you should try to get everything. Use the flail is for when he is in a straight line, the crystal storm for close up attacking, and the shotgun for extra damage.
First mine some admanite which can be gotten by destroying demon or crimson altars.Then fight the 3 mechanical bosses.Then go fight plantera.Then enter the dungeon for more better weapons.Then kill the cultists that spawn the lunatic cultist.Then kill dukefishron.At last the golem.If you are ready for the bigger challenge, go challenge the MOON LORD.
You should farm for souls to fight mechanical bosses.
also try to get wings by killing wyverns and harpies (there is better wings but check the wiki for those) http://terraria.gamepedia.com/Wings
After you defeat the Wall of flesh and get to hard mode, everything gets harder. If your board, try hacking into the lishard, or lihshaed, whatever. Anyway to do that you will need to trade or duplicate a "picsaw", it's strong enough to break the blocks that make the lishard temple. If your still board, try purifying the hallow or killing the three mech bosses. is your STILL board then you have no life. ;)
First, mine some demon/crimson alters with the pwnhammer. Then, get a cobalt/palladium drill/picaxe and mine mithrill/orchallium to make an anvil and a drill/picaxe. Now, get adamantite/titanium and make a forge, drill/picaxe sword, and armor. Now your ready to get some souls of flight.
Go to your sky island and just wait for a wyvern. Kill it and get souls of flight,repeat, and now get feathers from harpy's. Go to the underground Hallow/corruption/crimson for souls of night/light. Use those and combine souls of light/night, feathers, and souls of flight to make angel/demon wings.
Now go and defeat either the destroyer, twins, or skeletron prime.
Hope this helps!
First off, start by smashing demon altars and leaving only one behind for crafting purposes; then mine the other new ores that come from destroying demon altars (cobalt,mythril,adamantide and their other related type) to make good armour and weapons.
Then after fight one of the mechanical bosses to make the jungle spawn planteras buds; these can be destroyed to summon Plantera.
After defeating plantera you will receive the temple key which can be used to open the lihzard temple door inside The lihzard temple you will find a lihzard power cell which can be used summon the golem.
Once you've managed to beat the Golem, congratulations, you've covered a major milestone and it's time to try to take on some other bosses as well as work on your base and maybe make an armoury to keep your armour on mannequins, a museum for statues and frames,a variety of gardens, and so on.
Iff you think you've got what it takes, try the pumpkin moon or frost moon, and be sure to ready up a load of traps and defenses for your base; possibly even safehouse that you can hide in when the going gets tough.
If you get bored afterwards you can try a replay with a different style for self-imposed challenges.