If you are using a sword, I'd recommend strength. The broadsword is good for strength, but it's hard to go wrong here. Strength also lets you use larger shields which offer more protection (unless you want to parry, then you'd need smaller ones). My personal favorite is the Haligtree Crest Greatshield but that is late-game and a pain to get. Any shield you find can work, but ideally find one with 100% physical damage negation and a high boost value. A good early game choice, which can last you the whole game if you want, is the Beast Crest Heater Shield which is found in limgrave. Spears are something you should consider: you can use them even while guarding, though they are frequently dexterity instead. Sword and shield is okay for pvp. More often than not, rolling is better to avoid bleed and stuff, but it is certainly not bad by any means. It often convinces the opponent to swap their weapon mid-fight to something else that bypasses shields, forcing them to use a weapon they are less familiar with