In the bathroom, nothing beats an open able window that can be left open at all times to circulate fresh air from outside. If possible keep the option of a window that opens when developing your bathroom design. There are many different types of windows that mean they can be left open securely.
The most popular form powered of ventilation is the simple ceiling fan. Exhaust ceiling fans are installed in the ceiling, which then take the hot air & usually expel it into the ceiling/roof cavity. If you have a tiled or tin roof, the air will disperse and steam quite quickly.
If you are feeling really tricky, they can have a humidity sensor attached to them so they come on and turn off automatically.
Other options for ventilation include inline extraction fans, which carry the moist air through a vent in the ceiling & expel it through a fan that is mounted on the roof.
The use of insulated tubing cut down on noise, but the initial cost and the installation costs of running it to the exterior – usually via a vent mounted under the eave make it an effective, yet costly exercise.
There are various wall or window mounted fans if you do not have a roof cavity. I am yet to find one I like the look of that works well though!
Having good ventilation is instrumental in the long lifespan of your bathroom. Having a damp, humid room isn’t good for the paint, the grouting let alone the plaster board on the ceiling.
Giving serious thought to optimising your ventilation will go a long way.