I believe maths and science tend to be made overly complicated because it is taught from a purely theoretical stand point. As an engineering student I find it easier to teach and understand when you contextualise it into the real world. When what you are learning is connected to what you see everyday I believe it is so much easier to understand and that forms the core of my tutoring.
I do not believe that the duration should be set since people have very different concentration durations so the dynamics can and will be changed to suit the person.
Whilst I have little formal tutoring experience I have helped alot of family friends children to prepare for exams. To me this is valuable experience because I learnt how different peoples learning can be and I believe this will be a great skill I can apply to my students.