Fischl is a bow-wielding Electro user who is proving to be a strong prospect in Genshin Impact. To get the most out of her, you really want to lean into boosting the damage of her abilities. She will grow stronger as you level her up by getting duplicate characters, but the below weapons and artifacts will be great options for her, regardless of her level.
As a bow user, we are once again looking at the Favonious Warbow or The Stringless, both of which can be obtained from Wishes. The Favonius Warbow will give Crits a 60 to 100% chance to generate elemental orbs that will regenerate 6 energy, allowing you to cast abilities more often. This is important, because Fischl’s abilities are where the majority of her power lies.
The Stringless will directly buff her elemental skill and elemental burst damage by 24 to 48%, making it a fantastic option to use on her. A final option for Fischl is the Rust Bow, this will directly increase her basic attacks, but decrease her Aimed Shot damage by 10%. It is a valid option on Fischl as you should be building her attack stats to maximize her ability damage.
You have a couple of choices for good artifact sets for Fischl, and to make things better you can get a great result by splitting two of them to gain double two-item buffs. The Gambler set will give a 20% increase to elemental skill damage, while the Thundering Fury set will provide a 15% boost to Electro damage.
You can farm for the Gambler Set at the Clear Pool and Mountain Cavern in Jueyun Karts in Liyue, and the Thundering Fury set can be farmed at the Midsummer Courtyard in Starsnatch Cliffs in Mondstadt.
You can also happily double down on either set, going for the full set bonus if you prefer, or just want to focus farming on getting a full set before moving on to the next one.