You start with 3 Horadric scrolls, but can only pick one up if you don't have any.
So to make a doll stash give Wirts Leg to a new character, make the stash with the new character, then toss this stash and the third scroll on the ground, leave & delete this new char. Come into the game with your main character, pick up the stash and the one scroll. Cube the stash with the scroll and it'll get your main character's name (until then it has the name of the now deleted character that created it).
You can have one of each type of unique charm (there are several for each size) per character.
Damien drops runes, not the black key; he's in level 3 of The Swampy Pit (same clearing as theFlayer Jungle waypoint). Under Nihlathak is the entry to The Dungeon, on level 14 of that dungeon you meet the Ancient Diablo, he'll give you the black key if you ask the right way...
From Rogues' Camp there are new entry points into the PVP area (if you're a pack-rat like me, and generally have a full inventory, stash, and cube, go to the PVP area to toss your full cube to do normal cubing); one to the graveyard where your stash is (make all your mules of level high enough to go to the stash unassisted before stuffing them fulll of valuables); and one to the Underground Passage to get to Stoney Field and Dark Wood (as in the Cain quest). The Cold Plains waypoint is one-way->Rogues Camp. In Tristram there is a hidden waypoint: near the right corner of map, behind a wall corner with your character facing you. Don't open sliding walls in the Barracks/Jail/Cat4, you could meet the Butcher (wait till level 40 to tackle him) or King Leoric (beware of a nasty Bone Spirit). Cat 4 is totally new and teleport doesn't work there very well.
In act 1 areas 1-3 many monsters drop an 'elicer', it gives 500exp. Useful for new characters. Also, a tristram-like portal can open in act 1 bloodmoor, to the non-name area (monsters are about level 33).
Level 2 of the sewers is totally new, that's where Drognan is (with your stash). Your stash is also in the lower left corner of town. Fara doesn't heal, but Atma does.
In act 3 your stash is in Travincal.
In act 4 your stash is by the River of Flames waypoint.
In act 5 your stash is on the right edge of the map at the same distance from town as Shenk.
Always use the 'gambler' to sell stuff, they buy for full price without limits (as if selling in Hell). Yellow/Green potions sell the best (for easily found stuff). Books, 'special elixer', 'tails', and 'souls' sell the very best.