Analyze it and get a score like this:
The Face – Check your smile, jawline and “squinch”.
Composition is also important ie. appropriate zoom, face position and uniform background.
Editing – image properties like brightness, contrast, etc.
You can analyze your profile pic right here:
https://www.snappr.co/photo-analyzer/
Snappr’s Photo Analyzer uses the latest research, combined with image recognition and machine learning technologies, to determine how well your photo will perform.