How are my Speaking responses scored?

Answer 1

Your best source of information is www.ets.org/toefl

You can find everything about scoring in general here:

http://www.ets.org/toefl/teachers_advisors/scores/

And also the official ETS Speaking rubrics that are used for scoring: http://www.ets.org/s/toefl/pdf/toefl_speaking_rubrics.pdf