To prevent your bathroom mirror from fogging up, you can try the following methods:

Use a mirror defogger: There are various mirror defogging products available in the market that can be applied to the surface of the mirror. These products create a thin layer that prevents fog from forming on the mirror.

Apply shaving cream or dish soap: Apply a small amount of shaving cream or a thin layer of dish soap to the mirror surface. Then, wipe it off with a clean, dry cloth. This helps to create a barrier on the mirror, preventing fog from sticking to the surface.

Use a hairdryer: Before taking a shower or bath, use a hairdryer on low heat to blow warm air across the mirror surface. This will help to raise the temperature of the mirror, reducing the potential for fog to form.

Increase ventilation: Improve the ventilation in your bathroom by using exhaust fans or opening windows. Proper air circulation helps to reduce humidity levels, minimizing the chances of fogging.

Preheat the bathroom: If possible, preheat your bathroom before taking a shower or bath. This can be done by turning up the heat or using a space heater. A warmer bathroom reduces the temperature difference between the mirror and the surrounding air, preventing fog from forming.

Wipe the mirror dry: After showering or bathing, use a clean, dry cloth or towel to wipe off any moisture from the mirror surface. This can help to prevent fog buildup.