i) Materials, Techniques and Processes basically encompass the process of creating the art form, and then how they created the subject matter and composition. If you were talking about an Oil on Canvas, you would talk about how they created the frame, stretched the material, coated with gesso etc. if you were to primarily focus on Materials and Creation. However I believe you can talk about how they actually created the piece, for example, painting the background first and moving into the foreground, whilst obviously explaining all the processes involved in that.
ii)Like spherelin said, talk about how the artworks were presented as you walked through the galleries, talk about how they evoked certain emotions etc. You don't have to talk specifically about how you felt, but it is wise to mention why things are placed where they are and how that makes the viewer react.