Original text:
I stretch my arms as I get out of bed. Then I walk to the kitchen and make a quick breakfast. I study carefully in a quiet library and take short breaks to relax. I come home from school and relax on the couch before making dinner. Phew! I brush my teeth, turn off the lights, and get into bed.
This paragraph has two related sentences at the beginning that could use a comma to show the flow of activities. It is also has some missing commas in two sentences: before a "fan boy", and before an additional statement.
This is how I would write it:
I stretch my arms as I get out of bed, then I walk to the kitchen and make a quick breakfast. I study carefully in a quiet library, and take short breaks to relax. I come home from school and relax on the couch, before making dinner. Phew! I brush my teeth, turn off the lights, and get into bed.