Condensation in the bathroom is a common problem. If the surface of walls, tiles and porcelain is cold enough and there is enough hot water vapour in the air, then condensation will occur. The problem is, when there is condensation, mould and mildew follow.
Take cooler showers and baths, so less heat and moisture is released into the air.
Install an electric exhaust fan in the ceiling and use it every time you bathe or shower. Most condensation is caused by poor ventilation. The fan will remove hot, moist air from the bathroom.
Use a dehumidifier to remove moisture from the air and store it as water in a reservoir. Empty this reservoir regularly or the water will evaporate back into the air.
Remove carpet from the bathroom. Carpet holds moisture, which keeps the humidity level high and contributes to condensation. Consider alternative floor coverings, such as tile made especially for bathrooms.
Remove potted plants. The soil in potted plants holds water and contributes to condensation.
Check for leaks. Even a small leak can add to humidity and condensation and cause mould growth. Check all pipework, especially around connections. Take a close look at the shower tray and bathtub to make sure all seals are intact.
Repaint the walls and ceiling with low-moisture paint made especially for bathrooms. This will keep the moisture down in the bathroom and limit condensation.
You can try opening your bathroom window to vent the room, but if it's cold outside, the cold air will contribute to condensation.