@Eljay The most important thing to remember is your lock-on mechanic. Never use the Humanity Item unless you absolutely need to. Never use the consumable souls that you find lying around until you are safely at a bonfire and ready to level up yourself/your gear. Here is a list of some of my favorite Humanity/Souls farming spots:
The Depths. just keep killing the rats, and keep your liquid humanity meter high enough to avoid getting cursed. There is a nice circle/roundabout way of getting back to the bonfire.
Tomb of the Giants. This is really late game but those infinitely spawning baby skeletons are great. I got 40+ humanity in a single hour farming there with the Gold Covetous Serpent Ring(found in Sen's Fortress).
The Darkroot Forest: The demon trees fall easily enough, and drop moss in usefully high quantities!
Anor Londo: Around the first Bonfire there are a lot of Giants, it's easy to aggro them one by one.
Painted World of Ariamis. Go back to the Asylum, parry the Black Knight to death and get the strange doll. then go to the painting in Anor Londo, find a way to open the gate, and then go ham on the phalanx hollows (pyromancy preferred)
Also, be sure to buy lots of Rings of Sacrifice from Oswald the Pardoner. And have a Rare Ring of Sacrifice ready for the boss fight with Sceath the Scaleless.
Never played DS2, didn't look interesting enough.
Bloodborne is an entirely different beast (pun intended). For starters, I would pick the "Violent Past" origin and the Hunter Axe as a starting weapon, Violent Past gives you the highest base strength and the Hunter Axe scales with strength. Be wary of Insight, I would recommend keeping it above one at least so you can level up. at 10 Insight you can summon help/invade. Insight stops being useful after 40.
as with the consumable Souls in Dark Souls, Bloodborne has ColdBlood, which can be consumed for free Blood Echoes. Again: DO NOT CONSUME THEM OUTSIDE THE SAFETY OF THE HUNTER'S DREAM.
That's all I know about Bloodborne, for now. I would suggest seeking help on YouTube from VaatiVidya or EpicNameBro. I hope that this has been helpful and as always: Prepare to Die.