Melee carries are rarely seen because that makes it easier for the enemy to focus a squishy in a team fight. That is why Fioras parry, ultimate, Frozen Mallet, and cleanse are extremely important. If you are a melee chances are you will be hit by crowd control more often, cleanse will get rid of all cc on you and shorten any other crowd control for the next 3 seconds. When playing Fiora in a team fight save cleanse until you are hit by a hard cc like a stun. and when first going in to a team fight try to quickly take the enemy carry, lunge to one of their melees then use the second lunge to reach the ranged carry, quickly w then e and when the enemies start to turn back on you ult. I would not reccommend going for an enemy ranged carry if your ult is not up for that plays an extremely important role. And know the enemies because if you try to get an urgot and he suppresses you then its game over.

On the Offtank Mercury Treads will help with crowd control so that your E will give the attack speed for Wits End, Madreds Bloodrazor, and Black Cleaavers on hit effects. The on hit effects will also apply when using your ultimate. Your Lunge and Burst of Speed will keep you close enough to enemies for the Sunfire Cape does damage, Sunfire Cape is also great for survivability and helps Fiora a lot since she is normally squishy and has no AoE.