Here are some example mountings and methods to help you choose how to go about installing your lights.
Again, these are just examples and please use this list as a starting point to work out your particular needs.
Handlebar mountings are the most popular choice with the type of mounting governed by the weight of the lamp unit and on whether they are designed to be easily detatchable or permanently fixed.
This light made by Buchel has a rubber fixing band so that it can be quickly and easily installed and removed.
With this type made by Cateye, there is a more robust fixing that is designed to remain in place on the handlebar while the lamp unit can be unclipped and removed for long-term parking.
This model from Oxford has a permanent fixing secured to the handlebar with an allen screw.
Here is a dynamo headlight from Buchel that fixes to a bolt at the top of the front forks. In earlier times, this bolt would have been used to fix the caliper brakes and perhaps the mudguard.
This type of light is not easy to remove and is intended to be a permanently fixed in place.
Where there is no mounting hole at the top of the forks, this handlebar adaptor bracket from Busch & Muller can be used instead.
Again we see a variety of fixings but also more choice on where to mount the lamp.
In the UK, the most common placing is on the seatpost. In earlier times, the rear fork would have been most popular.
In mainland Europe where most bikes will have a luggage carrier fitted, the rear of the carrier or the rear mudguard is more popular.
A typical seat post fixing lamp. This one from Buchel.
This type is not advisable where a carrier is fitted as any luggage will obscure it from view.
This battery powered carrier lamp from Busch & Muller fixes to the rear of the luggage carrier.
The same type is widely available as a dynamo version.
Mudguard lights mount to the stays fixing screw normally provided at the rear of the mudguard.
This example from Buchel can be battery or dydnamo powered.