Use the same spray count
Start with a similar number of sprays on separate areas or on two comparable days so one fragrance does not gain an advantage from heavier application.
Do not layer them on the same spot
Spraying both fragrances in the same place blends them together and makes the comparison harder to read. Keep application points separate.
Compare more than the opening
Check the opening after a few minutes, the middle later on and the drydown after several hours. Some fragrances lead early and become quieter later, or the reverse.
Track what matters to you
Compare comfort, setting, season, versatility, longevity, projection and price instead of searching for one universal winner.
Repeat the test if the result is close
Weather, olfactory fatigue and daily conditions can influence your impression. A second wear can prevent a decision based on one unusual day.