Work on your basics.
Take a step back, take a deep breath, and go play Garen in normal games.
Fiora is a rather complex champion in my opinion and you're probably distracting yourself more than you are helping yourself trying to use her. That isn't to say you're not ready or you may not be good at her, I'm just saying that if you have a bad and compromising flaw, you're going to have trouble noticing it while your brain is occupied with making Fiora work.
Especially if you're stuck in bronze and not climbing, it simply means the necessary side skills you need to operate a champion are probably not developed at all. "You learned how to run before you could walk" sort of thing. The obvious one is CS: Nobody expects you to be perfect but you need to learn how to farm at least 80% of your minions without overly trying. Another one is knowing how to trade in the short term, that is, knowing how to beat a matchup. Third is trading for the long term, for example you may be winning fights a lot in top lane but none of that will matter if you can't turn it into objectives for your entire team. Fourth is knowing how to play when you are losing or disadvantaged, as you NEVER play a top laner while losing the same way you play a top laner while winning. Finally, fifth is simply turning all the knowledge you gained from the last 4 steps into subconscious thinking and/or common sense.
