Fancy Fencing Rapier is a solo carry weapon and scales itself with the help of Piercing Arrow. You need some time to ramp, therefore it's recommended to use double big shield in particular Moon Shield with double armors. Moon Armor is important, Vampiric Armor is replaceable with Stone Armor. Moon Shields can generate so much mana that Mana Orb triggers instantly for extra buffs. Djinn Lamp can trigger fast with the help of Mana Orb.
Make Fancy as fast as possible with the help of Fanny Packs, Gloves and Maneki-nekos.
Oil Lamp gives accuracy that Fancy hits more after ramping up.
Amulet of Energy is by far the best amulet but Amulet of Steel can be useful aswell.
Useful potions are especially Divine Potions and Strong Heroic Potion can be helpful aswell.
Caps and Boots for the late game are good defensive items to get more gem slots aswell.
Purple Gems for anti heal are best for defensive. Use Yellow Gems to make Rapier even faster or Red Gems can help survivability aswell especially with Vampiric Armor because you lose health in exchange for armor.
Take skills that make Rapier stronger or give you more defensive.