Across 1,148 ranked games on patch 16.21 in Master and above, Tristana mains win 49.3% of their games in the bot lane.
Their most common build appears in 77.9% of those games and wins 51.0% of its 894 games.
It starts 
two Health Potions and 
Doran's Bow, completes 
Yun Tal Wildarrows, 
Infinity Edge, 
Navori Flickerblade, 
Lord Dominik's Regards and 
Bloodthirster in that order, and takes 
Berserker's Greaves.
Two other builds are played often enough in the bot lane to be measured on their own.
In the bot lane, Tristana mains fare best against 
Varus (won 61.3% of 31 games), 
Ezreal (won 59.5% of 37 games) and 
Jinx (won 58.5% of 41 games).
Their hardest matchups, the champions that counter Tristana, are 
Xayah (won 29.3% of 41 games), 
Aphelios (won 30.6% of 36 games) and 
Kalista (won 32.1% of 28 games).