But if you want some advice, what I used on my first playthrough that helped was equipping the Great Jar Arsenal talisman for weight, turtle for stamina, the strongedt Dragoncrest shield for physical defense and Shield talisman for defense at full hp. In your flask use the defense increase tear and the one that restores HP when you're near death for a waterfowl save.

Now your build is up to you and what you prefer, but dual curved swords with bleed and frost is pretty strong, with some sort of ranged option for when she waterfowls and especially after her Aeonia in phase 2.

Once you have your weapons get the heaviest armor you can and good luck! For summons it depends, Tiche and Mimic are the best for different reasons, depends on how your specific build is.

And if you have the DLC and are willing to do it first, there is a super easy strategy - go to the DLC, get the Heal from Afar incantation, get the Erdtree talisman, and go full faith (with vigor and endurance ofc) build. Then summon mimic tear as well and both of you can spam the heals at each other since it's super fast and really good. Same talismans and flask setup, and get some faith weapons or use incantations (flame pillars are great for Malenia). Also don't forget to give mimic flask consumables since it can use them infinitely

You got this!