Across 642 ranked games on patch 16.21 in Master and above, Miss Fortune mains win 51.4% of their games in the bot lane.
Their most common build appears in 41.0% of those games and wins 52.5% of its 263 games.
It starts 
two Health Potions and 
Doran's Bow, completes 
Bloodthirster, 
The Collector, 
Infinity Edge and 
Lord Dominik's Regards in that order, and takes 
Boots.
Three other builds are played often enough in the bot lane to be measured on their own.
In the bot lane, Miss Fortune mains fare best against 
Tristana (won 65.0% of 20 games), 
Jhin (won 61.5% of 26 games) and 
Caitlyn (won 60.0% of 10 games).
Their hardest matchups, the champions that counter Miss Fortune, are 
Draven (won 23.1% of 13 games), 
Jinx (won 28.6% of 14 games) and 
Kai'Sa (won 33.3% of 15 games).