(1) Shivering in the snow, my sister and I pressed closer to our mother for warmth. (2) I was wearing black gloves. (3) As we waited in line to get inside the job center, I felt embarrassed at the way those passing by looked at my family. (4) I missed our old, warm house, and the safe life we'd left behind. My mother's face was lined with worry.
You would be able to eliminate the second sentence, "I was wearing black gloves." This is not necessary to the story, and the sudden sentence feels almost abrupt and sudden. It causes the flow of the paragraph to slow and feel unnatural. The first sentence sets the scene and setting of the paragraph, which is why it is important that it is not omitted or gotten rid of. The third sentence continues to explain what is happening and why the narrator and their sister were pressed together, showing why they were even out in the cold. This could not be omitted. The fourth sentence explains how the narrator feels about the situation they are currently in, something that although not necessary, is important to a story-line and helps show how the narrator feels about being at the job center. The story could continue without knowing the narrator was wearing black gloves, and this is why getting rid of the second sentence during revision is best.