As a suggestion for something to write about, read the newspaper and pick an article that you agree or disagree with and write your views on the matter.
Here is my version of your writing:
I went shopping today. Since it is Christmas time, I was in the queue to pay my bill for over 15 minutes. When I finally went to the cash register the employee could not scan the item because price tag was missing from the coat I wanted to buy. So I waited few more minutes to pay for my stuff.
I walked around all day in the mall; my heels are hurting now. I go to the mall every often; sometimes I buy few things and sometimes I just window shop. It is one of my favourite things that I do, especially in winter. I also enjoy seeing the Christmas decorations in different stores.