
Clear out the harder areas, like the Ringed City, to bring up your skills.
Collect all available Rings (note - all lower versions of rings are still available in all subsequent playthroughs, so don't worry if you missed any). Collect all Estus Shards and Undead Bone Shards. Kill off all Crystal Lizards and Ravenous Crystal Lizards. Trade everything you want to trade with Pickle Pee, Pump-a-Rum. Obtain all Titanite Slabs - there are fifteen (eight in the base game, three in the Ashes of Ariandel DLC, and four in The Ringed City DLC) available per playthrough so it is highly recommended to get as many as possible per run. Pickle Pee, Pump-a-Rum trade state - all trades are reset except for the head carvings, of which you can only have one of each. NPC quest progression resets, dead NPCs come back to life, NPC invaders will invade again, etc.) This includes Dark Sigils, Tomes, and Ashes (and their respective vendor ware unlocks). (if you kept the unique Young White Branch he gave you) Friendship with Giant of the Undead Settlement. All your current stats, weapons, armor, and consumables. Covenant rank status/all covenants and covenant rewards. NG+ is variable based on the location of the game the enemy is in and NG+2 through NG+7 multipliers use NG+ as a base. There are an unlimited number of NG+, but enemies stop getting stronger after NG+7. From NG+3, the only known changes are enemy health, defense, resistance, damage, stamina damage, and the souls gained for killing enemies and NPC's. Soul pickups are changed to higher level versions which give more souls when consumed or sold. Access to upgraded Rings: +1 for NG+ and +2/+3 for NG++. Contrary to the bottom, but confirmed in Microsoft Excel (Yhorm and Iudex were tested, they don't have the same rate of health progression), the HP increase is variable. Enemies have more hit points, and deal increased damage.
The consecutive playthroughs bring new challenges as enemies have increased health and damage, and there are new Souls and Rings hidden for players to find in order to continue developing their character. After the credits, players are presented with an option to head straight into the next playthrough if they opt not to, they can start the next playthrough later, from the Firelink Shrine bonfire. New Game Plus is a feature of Dark Souls 3, wherein once the Final Boss is defeated, players have the option of replaying the game with their current stats and gear.