How to get cool items fast?

[Rimpula]

I've just been digging for ages. Is that for item finding goes?

[Zurkol]

Search for chests and dungeons, if u find a golden key u should go in the sky and look for islands ;D

[Fallenliam]

you don't need a key for sky chest. and one of the best ways to progress the game is to kill the Eater of Worlds or Brain of Cthulu or Eye of Cthulu. You get their ore drops and can then harvest the best minerals for prehardmode. If your searching for accesorys then the killing Skeletor is your best options and then taking on the dungeon. Other then that dig around looking for the odd ball chest and work your way up in armor and weapons before going to hardmode

[tasty tapeworms]

You dont need a key for a sky island but i know how to find one easily. Use the waterbolt and shoot it in the air, if you can hear the impact there is a sky island. I also recommend getting the shadow key and go to hell. If you find any locked chests in hell open them up. Once you get strong enough you can kill the wall of flesh easily and get good loot for early hardmore (Get all the emblems). After you defeated the wall of flesh and defeat the mechanical bosses you can craft good stuff and post-plantera, go grind the dungeon and kill the golem in the lihzarhd and get a bunch of cool stuff. At the end game, kill Duke Fishron and try and get the loot from the pumpkin/frost moon.
For Plantera, Golem, Duke fishron and the moon events, do them lots of times to ensure you get all the good loot they give.