fine-tune fine-tune /ˈfaɪnˈtun/

verb

1. Make fine adjustments or divide into marked intervals for optimal measuring  ( fine-tune , graduate , calibrate )
   make fine adjustments or divide into marked intervals for optimal measuring
    Calibrate an instrument
   calibrate an instrument
    Graduate a cylinder
   graduate a cylinder
   
2. Adjust finely  ( fine-tune , tweak )
   adjust finely
    Fine-tune the engine
   fine-tune the engine
   
3. Improve or perfect by pruning or polishing  ( down [Informal] , fine-tune , refine , polish )
   improve or perfect by pruning or polishing
    Refine one's style of writing
   refine one's style of writing