A Skull Cavern run that gets past the first few floors
Choose whether this trip is for depth or loot before you leave home. Every side path to one more ore node spends time you could be using on the next floor.
Set the morning up before bed
Group weapon, pickaxe, bombs, healing food and staircases in accessible hotbar slots. Keep plain healing food separate from a buff meal so healing does not overwrite a useful food buff. A Desert Warp Totem lets you leave before the normal bus trip; keep it out of the bomb slot so it is not activated by mistake. On arrival, go directly to the cave instead of stopping at every forage spot.
Budget staircases for slow floors
At Mining level 2 you can craft one staircase from 99 stone. Alternatively, take jade to the Desert Trader on Sunday: one jade buys one staircase. Save several for a long spiral, crowded room or infested floor. Place one on an open floor tile and interact with it; it is a one-floor descent. Keep enough space between yourself and an approaching serpent to place and use it safely.
Take an exit when you uncover one
Target a dense group of breakable rocks; place a bomb, step outside its blast and look for a ladder or shaft. For a depth run, take the exit instead of clearing the rest of the room. A shaft can skip multiple floors but costs health, so heal before jumping if nearby enemies could finish you on landing. Skull Cavern has no normal elevator; pack another descent kit instead of expecting the last depth to remain selectable tomorrow.