Fiora is a champion that rely on true damage that scales with AD, so we just buil tankiness and AD right? Exactly, we want as much HP and AD as possible. At the end of the build your R should do about 50% of enemy's health, combine this with 200% crit on her E and 15% max health damage from passive and u have a monster with 6k HP (with sterak's even more cause of shield). early will be hard cause you build hearsteel so dont rush, just gather farm and stacks and after second item u can fight. Let me know if this was helpful and give this build a try!