Check the serial and model numbers
Verify the weight and build quality
Inspect the dial for alignment and printing quality
Examine the movement with a professional
Look at the cyclops magnification
Test the second hand movement
Check the crown logo and engravings
Inspect the case back
Verify the bracelet and clasp details
Compare the watch to official Rolex specifications
Check for proper documentation and box
Have it authenticated by a Rolex dealer or watchmaker