Old stories are the best, as Shakespeare knew.
You cannot copy them directly, of course, but you can re-work, re-version and re-invigorate them.
Exercise
• re-create a scene from a TV drama
• choose any mass-market novel at random, read the opening, decide what the writer was trying to achieve and improve it
• write your own version of a scene from a fairytale
Source: 365 ways to get you Writing, Jane Cooper, How to Books, 2012