Before we start, I wanna tell something first... I played too many games with her, so I was disappointed because she doesn't have AP. Well, someone call me crazy, because I am making AP champion from Fiora, but when she do Q, Q, R, that 340 AP is much better than more 100 damage... When, if you wanna see how to play aggressively with Fiona, look at this guide... I think everyone knows how to play positional with Fiora, but to take triple kill, now that is something... This is my first guide, so if you have something to say, please comment, I will read it...

I think that Runes are about how you wanna play. Here I will recommend everything for AP and Life Steal or maybe armor penetration.

13-0-7 is unusual, but I think it's the best if you wanna play aggressively. You don't need defense, so choose Utility and Offense on your own, but I recommend this. It's a question of your personal style.

To start with buy boots and 4-5 Health potion, because you are going to use as much as possible HP. Doran's ring can be useful with 15 AP, 100 HP and 5 mana regain. After this we are going to build boots, and Ability Power. If you think you are losing too much HP, go and buy some Life Steal. With built showed above you will be great champion, but remember, let someone go before you, and then press R, and it's over for them... Which Item you should buy we will see in the Chapters by names: Early Game, Middle Game and Late Game.

It doesn't really matter, because all her Skills are great, if you know how to use it, but I take W first, and then take Q for ganking and bot be ganked, and also for defend turret, and E when you think so. Ulti take whenever you can. it's the greatest skill you have.

I recommend Ghost and Ignite, or Ghost and Exhaust.
Flash is very good on ganking, cause you can do Q on him very fast, but flash can't really help you not to be ganked, 'cause you already have your Q, so I think Ghost is much better Spell.
Teleport is not from use here, 'cause at the beginning you have many Health potions, for ganking it's terrible, 'cause they see where will you come, and for not to be ganked is more terrible because it takes too much time.
All other Summoners Spells are also terrible for her.

If you have a jungler, go solo top, because you cannot do anything before reaching 6 lvl, but you can stay at turret and not let them aim it. You need to practice a lot. If there isn't a jungler in your team, go with someone top, or bottom. DON'T check bushes, because you will probably die. Until reaching 6 lvl, play defensive, or if you are sure you are going to kill someone, press Q, Q, you reached him sure, W for reflecting his attack, and E for faster Attack Speed. DON'T try to kill someone at low HP, when there is his teammates nearby. If your opponents in your line are Garen and Pantheon, take some archer with you, or change line with someone else, because if you stay there, you can't farm minions, and you are going not to have enough gold.

After reaching 6th lvl, you can go gank, or stay at your line. Anyway, you can't be killed easily now, because of your ulti. But, REMEMBER, don't use your R on Fizz or Vladimir, 'cause they can break out from it. Before your 12th lvl you should buy Sanguine Blade. Before 15th lvl you should have enough gold from ganking for Hextech gunblade.
How to gank?
Well, you can fight him with your E + basic attacks, when he tries to get away, press q, again q (you don't lose your mana on second time), eventually Exhaust should be enough, if he still have some HP, press R, and he is dead for sure.
How not to be ganked?
Always be with your teammates, and look at the minimap... When you see someone is missing, press Tab, you'll see if he is dead, but play little def. usually your teammates will say something like ss (ss is signal to there is no Champion in his lane), or yellow ping on you. But even when they come to you, you can always use Ghost, with Q on their minion, and you can freely ran away.

After Hextech gunblade, you need Guinsoo's Rageblade before your 18th lvl. When you reach lvl 18, you should go to the base and buy Randuins Omen. Now you have awesome Blade Waltz because of your AP, you have good armor, and big amount of Health points, and you have some life steal. Now you are playing team fights, with your R, and then stay out, because you've taken them about 1/3 HP, so your teammates should defeat them, if they cant beat them, you can go into fight again cause you have high damage and attack speed, just be careful with your HP. If they have bigger damage then your team, start with Q, Q, W, E and then fight, when your Healths go under 400, use your Ulti, you will probably have something like triple kill.

Well, you can go jungling for a while, or you can say to your team that you need more golds, and ask someone to help or leave your lane. If they take too many of your HP, it's good idea to change line with someone. Also, good idea is to thank them for letting you take KS (kill steal), if they don't need so much gold.