These are my shortcuts that significantly speed up my workflow.

Essential Shortcuts

When a layer is selected:

• P: Position

• R: Rotation

• S: Scale

• T: Opacity

• M: Show Mask Path

• F: Show Mask Feather

• Command + Shift + R: To set a keyframe for rotation instantly.

• U: to reveal all modified properties.

  
  

Pressing U reveals all keyframes for the selected layer.
Instead of sifting through the entire layer,
you can see animated properties right away.

Additional Essential Shortcuts

• Spacebar: Play/Pause

• Command + Arrow Left: Jump one frame to the left.

• Command + Arrow Right: Jump one frame to the right.

• B and N: Set the beginning and end of the work area.

• Ctrl/Cmd + D: Duplicate layers.

• V: Selection Tool

• G: Pen Tool

• Y: Pan Behind (Anchor Point) Tool

• Option + Command + M to send the project to Media Encoder.

  
  

Plugins

I also love using the FX Console plugin from Video Copilot: FX Console.
It allows me to quickly search an effects to the selected composition.