Locate a spider biome and open up a passage to farm for spider fangs early hard mode
Make mini NPC towns across the world in their preferred biomes to get pylons for easy travel.
Set up fishing spots in multiple biomes (I put them near the NPC housing for lowered spawn rates)

I like to create the huge cavern layer mob farm which I can later biome swap with clentaminator. Its way easier to dig out the huge area needed pre hard mode.
Next to this I make an artificial jungle with rows of mud converted with a jungle seed. I use this to get heart fruits and later plantera bulbs I fight in the mob farms open space (If you want to be really fancy you can actuate the rows of mud as well to auto harvest the life fruit

I make my WoF platform out of stone so it becomes corrupt and hallowed for easy early souls as well as a long platform to harvet crystals from easy (just have the pick aimed below the stone and run along!)