Have a Dextarity and Strength Character
Outside of magic, the two main types of weapon/armor classes are Dextarity and Strength, both of which have their own pros and cons. Dex builds are typically very fast and rely on quick successive hits from weapons types such as dual swords or whips. On the flip side, Strength is far more focused on slow, deliberate hits that do large chunks of damage on opponents.
Given there is no doubt going to be a ton of new loot in The Ringed City, having both builds covered will allow you to experiment and see which weapons you like best. This will not only allow you to experiment when playing, but won’t require you to roll an entirely new character just to try out a piece of gear you found in this expansion. You’ll also want to make sure that you’re stocked up on Titanite Shards of all types so you can quickly upgrade your weapons once you get them.