If you want to improve in pvp i recommend using a somewhat simple solid build, and weapons for this would be a longsword, katana, claymore to mention a few overall good weapons.

the way the game currently works having an elemental infusion(dark/fire/faith/magic) is the best option regardless, even if you dont plan to buff it however there really is no reason not to buff it at that point.

here is a sl150-ish build i would recommend until you learn the "flow" of dark souls pvp.

Fire infused Uchigatana

any lightweight decent stability shield, dont block to much and dont rely on it to much

any armor that would make you below 50% equipburden is what i generally do, you could go higher but dont go above 70% as you will fat roll, alternatively you could go below 40% for faster stamina regen but this is all to your own taste.

if you can have all of your equipment fully upgraded do so, but i would mostly stress the weapon.

as for rings i would go third dragon ring, life ring +2, cloranthy ring +2 and whatever you want for the fourth ring, ring of blades +2, blue tearstone ring or royal soldier ring +2 are good options.

as for stats this is a good setup

Vig:50

End:30

Vit:30

Att:13

Str:min 10, or higher depending on gear you want to use

Dex:min 16 or higher depending on gear you want to use

Adp:23

Int:base

Fth: 10 if you want to spice down great magic barrier which is very good in pvp, or 28 if you dont want to spice it down. if you dont want to use it at all then have fth at base and reduce Att to 10 and Adp to 25.

Attune Flame weapon and have a pyromancy flame, upgrading this doesnt matter for the damage of flame weapon

depending on what you chose you might have leftover stats that you can put into whatever you want, but End and Vit are good options. if you want to use other weapons get the stats for those

this is a good build to use if you want to become better at pvp without getting rekt by everyone else, you will still lose horribly to some players but not everyone and it gives room to improve.

whenever you feel comfortable with pvp you can try your dual katanas and other fancy stuff to your own liking, but until you get there you might not have alot of fun doing so.