mid-late game with TP try split pushing while watching your team, maybe someone is getting caught but you can tp in to turn it. If your team is fighting and wins a fight while you are split pushing you keep going take towers. If you see the fight might be a loss tp in, but you gotta read it quick because if your late it might not matter and you might as well keep pushing. Ping your team back if you are split and know you can get a free tower so they avoid the 4v5 and free tower. I played a lot of Fiora, she seems like a situational pick to me when your team has good tanks/cc, but lacks damage.
I honestly try to rush the enemy tower down faster than anything top because once that is gone I'm looking to roam and make plays only going back to clear waves.
A way you can make TP ganks easier is tell bot to ward deep in the bush along the wall on the bot side of the map. When the enemy is pushed up to your tower you can get an easy flank.