So, I (my team) have a hard time against Fiora. I don't fight her often so I don't know how to combat her. Most of the time, some one else goes top, has to go against Fiora and she gets fed. I'm usually support and by the time laning phase is over, we get smacked.
Any tips against her? Who are the best champs to go against her and builds?
Go Singed vs her and own her, 1st item to build of course is a zhonya.
Rush armor, if you don't already.
I say this because I've seen too many match ups where people don't rush any resistances against champs that mostly do one type of damage.
makes her life hell at all stages of the game. Counterstrike nulifies all her damage, even her ult since each hit is coded as an auto attack. Jax is a better 1v1 late game champion, and Jax stomps her in lane if your any good with him.
Any tips against her? Who are the best champs to go against her and builds?
For tips against Fiora that aren't pick/ban specific:
The only way Fiora wins the lanning phase is forcing her opponent to 1v1 her. Her wave-clear is among the worst in the game, so she's pretty easy to out-CS through just being passive. You can also push and roam, or fast-push so every time she attempts to trade she has to deal with an army of minions. Fiora is also fairly unique in that she has nothing with range in her kit at all, at least anything that doesn't place her on top of an opponent. She can't poke, she has serious issues playing hit and run. If you have any poke at all - you can default to wearing Fiora down before engaging her.
Once Fiora actually gets Tiamat and can CS effectively - she's really, really, really, really suceptable to counter-builds.
Not only is her entire kit physical damage, but Blade Waltz actually counts as an auto-attack for the purposes of items like 
, and the AD steroid on Riposte and AS steroid on Burst of Speed are 100% auto-attacks, so 
hits that pretty hard. As a melee champion, 
and 
also do to Fiora what Thornmail does, except she doesn't need to AA you to take damage.
Fiora will win a damage race against most champions due to being 100% AA reliant scaling really, really, really well with Crit, Life steal, Armor Pen, AD, and AS - so if you're playing any champion with any excuse to get a defensive item, even if it's 
, you want to go for it.
It's worth noting with most top-lane match-ups the vast majority of fighters in the game grab 1 major offensive item if they're doing well or going even, then build defense for the rest of the game. If you're playing any of those - you build defense from the start.
Concerning playing vs. Fiora late - don't run in single-file against Fiora. She has an easy time transitioning from one duel to the next.
Her only team-fight prescience comes from her ult though, making her a fairly lackluster team-fighter in most regards, especially considering she's squishy, melee and melee range: making her very hard for her team to protect, very easy to focus, and easily killed inadvertently by AoE bombardments.
So - stick together vs. a Fiora late. Just keep an anti-Annie-pentakill formation when you do, where you're close enough to help one-another out, but not close enough for Fiora to get splash damage from Tiamat/Hydra. When she starts ulting, try spliting up to insure she doesn't get splash damage either.
Additionally: Fiora fallows her opponents when she ults, so you can lead her into really bad positions. You can lead her into turret deathzones or in a place where she has to fight a 1v5 post-ult to survive, so use the control over her mobility to your advantage.
As for counter-picks: any Fighter/Tank can abuse Fiora's extreme weakness to counter-building, so most of those give her hell in lane.
Jax, Pantheon, Teemo, and Quinn also give Fiora issues on the squishy side due to Blade Waltz counting as an auto-attack for the purposes of evasion, AA blocking, and blinds.
