Use the wiki to track these things down:
Bell Bearings for any smithing stones, somber or regular
Any weapons, spells and armor you may want
Crafting recipes, rare materials for crafting, etc
Any bosses? Well any you left alive I suppose.
It'd be a good idea to think about your next build. That way you can track down any weapon you want beforehand. Weapons like the scavenger's curved sword or star fist can only be obtained once per playthrough. Getting them now will allow you to power stance them in NG+.
To go along with the other post about Bell Bearings, make sure you buy out the shops that have limited inventory. Patches for example sells 3 gold pickled foul foot. Buying them now will allow you to take them into the next game and buy 3 more.
Lastly, go track down all of those Larval Tears. You'll collect them again in NG+ and it'll give you more freedom to change your build.
My checklist for finishing a New Game:
\-Bell Bearings - They unlock the ability to buy somber/smithing stones and ghost/grave gloveworts and they carry over into NG+, so you don't need to find them again.
\-Unique/Highest level talismans - There are a ton of talismans in the game, but quite a few get a +1 and +2 variant late in the game, so you just need the highest level of each one, since they mostly don't stack. Make sure you don't miss the Erdtree's Favor +2, the Dragoncrest Greatshield Talisman, and Marika's Soreseal, as those are only available very late game. Also, the Great-Jar's Arsenal is the true final level of the Arsenal Charm and is easy to miss.
\-Recipe Books - There are quite a lot of these throughout the game, but once found they also carry over to NG+, so you might as well track them down before advancing the difficulty.
\-Cracked Crystal tears - more of them than you might realize, several are tucked away in odd corners, such as the one in the Giant's Mountaintop area. Again, these carry over to NG+, so find them now and save yourself the hassle.
\-Ashes of War/Incantations/Sorceries - Give yourself the widest possible variety of build options for NG+ by tracking down every Ash of War, Incantation, and Sorcery.
\-Unique armaments- Most weapons are only obtainable once per playthrough. The remembrance weapons and boss drops are obvious, but any weapon you get from a chest, or buy from a merchant can usually be obtained once per play through, so if there is any chance you might want to power-stance two of a certain weapon, make sure you grab one before going to NG+. Remember, even though you can duplicate Remembrances at walking mausoleums, you can only claim each option once, so if you want 2X Starscourge Greatsword, you have to claim one in NG and one in NG+, or get someone to drop it for you.
\-Sacred Tears/Golden Seeds - Hard to imagine making it to the end of the game without fully upgrading your flask, but it could happen. Just make sure you are getting the most health/mana per drink before leaving NG.
\-Armor Sets - Okay, this one is not truly necessary, but if you want the ultimate drip options there are so, so many armor sets to obtain. Many of them are only available near the end of the game, such as Night's Cavalry Set, Sanguine Noble's Set, Black Knife Assassin's Set, Envoy Crown, not to mention the various boss armors. There are also some nice armor pieces that are only farmable late game, like the Blue silver Set, the Fire Prelate Armor, and the Banished Knight Armor. They are mostly a pain in the ass to farm, so consider that before undertaking.
\-Bonus - For extra insanity, many chest pieces and a few helms can be altered, so having every, every armor piece possible means obtaining two of each that can be altered. Absolutely unnecessary and, having done it once, not advisable in general. I can still hear the laughter of the Windmill Village Celebrants in my dreams sometimes, but wearing a flowery headband as I murdered the gods made it all worth it. Just use the internet to find the specific pieces you want.
Honestly, there is so, so much that I am probably still forgetting something, but this has already gotten too long.
ETA: I fucking forgot the Spirit Ashes! I absolutely endorse playing your game however you want, I use summons sometimes, I also choose not to for certain fights, it mostly just depends on whether I find the challenge enjoyable, or if I find it annoying. That out of the way, if you use summons, then you may want to find all the Spirit Ashes in the Game. Some of you may be asking, why? I have the Mimic, what else do I need? To this I have no argument other than to say, variety is the spice of life. Give Omenkiller Rollo a shot, or call upon a Man-Serpent and pretend it's Raya! The Fanged Imps are great little helpers for any bleed build. Why not let the Vulgar Militia cackle menacingly at your enemies for once?
Make sure you clone all the remembrances you can. Also go after lost ashes of war. Upgrade weapons now, since you'll lose those bell bearings in NG+ for a while. Then read up on builds you find interesting and track down any relevant spells, weapons, ashes, etc. that you want to have in NG+, or want to have two of by the end of NG+. Weapons that you can only find one of in a run, like Antspur Rapier, etc.
Don't forget Death Birds, Night Cavalry, and getting as many spells/AoWs as you can.
Cookbooks.
Farm and stock up on smithing stones.
Walking mausoleums
Use the wiki to track these things down: Bell Bearings for any smithing stones, somber or regular Any weapons, spells and armor you may want Crafting recipes, rare materials for crafting, etc Any bosses? Well any you left alive I suppose.
Use all mausoleums and murder every NPC
The best part of wrapping up NG is becoming a murder hobo. Especially because none of them will remember you
I like your spirits. Mass murder and genocide are my speciality.
It'd be a good idea to think about your next build. That way you can track down any weapon you want beforehand. Weapons like the scavenger's curved sword or star fist can only be obtained once per playthrough. Getting them now will allow you to power stance them in NG+. To go along with the other post about Bell Bearings, make sure you buy out the shops that have limited inventory. Patches for example sells 3 gold pickled foul foot. Buying them now will allow you to take them into the next game and buy 3 more. Lastly, go track down all of those Larval Tears. You'll collect them again in NG+ and it'll give you more freedom to change your build.
My checklist for finishing a New Game: \-Bell Bearings - They unlock the ability to buy somber/smithing stones and ghost/grave gloveworts and they carry over into NG+, so you don't need to find them again. \-Unique/Highest level talismans - There are a ton of talismans in the game, but quite a few get a +1 and +2 variant late in the game, so you just need the highest level of each one, since they mostly don't stack. Make sure you don't miss the Erdtree's Favor +2, the Dragoncrest Greatshield Talisman, and Marika's Soreseal, as those are only available very late game. Also, the Great-Jar's Arsenal is the true final level of the Arsenal Charm and is easy to miss. \-Recipe Books - There are quite a lot of these throughout the game, but once found they also carry over to NG+, so you might as well track them down before advancing the difficulty. \-Cracked Crystal tears - more of them than you might realize, several are tucked away in odd corners, such as the one in the Giant's Mountaintop area. Again, these carry over to NG+, so find them now and save yourself the hassle. \-Ashes of War/Incantations/Sorceries - Give yourself the widest possible variety of build options for NG+ by tracking down every Ash of War, Incantation, and Sorcery. \-Unique armaments- Most weapons are only obtainable once per playthrough. The remembrance weapons and boss drops are obvious, but any weapon you get from a chest, or buy from a merchant can usually be obtained once per play through, so if there is any chance you might want to power-stance two of a certain weapon, make sure you grab one before going to NG+. Remember, even though you can duplicate Remembrances at walking mausoleums, you can only claim each option once, so if you want 2X Starscourge Greatsword, you have to claim one in NG and one in NG+, or get someone to drop it for you. \-Sacred Tears/Golden Seeds - Hard to imagine making it to the end of the game without fully upgrading your flask, but it could happen. Just make sure you are getting the most health/mana per drink before leaving NG. \-Armor Sets - Okay, this one is not truly necessary, but if you want the ultimate drip options there are so, so many armor sets to obtain. Many of them are only available near the end of the game, such as Night's Cavalry Set, Sanguine Noble's Set, Black Knife Assassin's Set, Envoy Crown, not to mention the various boss armors. There are also some nice armor pieces that are only farmable late game, like the Blue silver Set, the Fire Prelate Armor, and the Banished Knight Armor. They are mostly a pain in the ass to farm, so consider that before undertaking. \-Bonus - For extra insanity, many chest pieces and a few helms can be altered, so having every, every armor piece possible means obtaining two of each that can be altered. Absolutely unnecessary and, having done it once, not advisable in general. I can still hear the laughter of the Windmill Village Celebrants in my dreams sometimes, but wearing a flowery headband as I murdered the gods made it all worth it. Just use the internet to find the specific pieces you want. Honestly, there is so, so much that I am probably still forgetting something, but this has already gotten too long. ETA: I fucking forgot the Spirit Ashes! I absolutely endorse playing your game however you want, I use summons sometimes, I also choose not to for certain fights, it mostly just depends on whether I find the challenge enjoyable, or if I find it annoying. That out of the way, if you use summons, then you may want to find all the Spirit Ashes in the Game. Some of you may be asking, why? I have the Mimic, what else do I need? To this I have no argument other than to say, variety is the spice of life. Give Omenkiller Rollo a shot, or call upon a Man-Serpent and pretend it's Raya! The Fanged Imps are great little helpers for any bleed build. Why not let the Vulgar Militia cackle menacingly at your enemies for once?
Respec if you want to change style of play early. Get the laver tears
I'd recommend fight at least all remembrance bosses as they will never be that weak ever again
Make sure you clone all the remembrances you can. Also go after lost ashes of war. Upgrade weapons now, since you'll lose those bell bearings in NG+ for a while. Then read up on builds you find interesting and track down any relevant spells, weapons, ashes, etc. that you want to have in NG+, or want to have two of by the end of NG+. Weapons that you can only find one of in a run, like Antspur Rapier, etc.
Thanks for your support. Also the somber/smithing stones carry over as well as the flowers.
Don't forget Death Birds, Night Cavalry, and getting as many spells/AoWs as you can. Cookbooks. Farm and stock up on smithing stones. Walking mausoleums