I try to incorporate reflection in my photography whenever possible. It can be extremely rewarding and lift the results to another level by creating drama in your scenes.
It is perhaps the easiest technique to master but at the same time a most difficult topic to get good results with. I like to think its a matter of mindset, as soon as you get it you will start to see interesting reflections in scenes you might before have judged as less interesting.
Seen from a pure technical perspective its is about getting good depth of focus and the right viewpoint. f/8-f/11 is again a good space to be in. Focus might sound easy, but when it comes to reflections it can be a bit trickery, should you place focus on your subject or the reflection or somewhere in between, the good answer is always “it depends”. How is distance between the subject and the reflection. What expression are you looking for, what do you want to draw attention to. I like to work my focus manually, giving me control of where i place attention and much depending how much i want to bring the reflection in play.
The last thing to consider is the angle of the light and how it affect the reflection. If you are shooting people you might have the luxury to manipulate their position in order to emphasise the reflection, but usually for me its not the case, instead I either wait for a subject to pass in the reflection or I will be exploring different viewpoints to find the angle at which the reflection is most visible.