Recently I have joined several short story/flash fiction contests. Though the monetary gain is a great motivator, the break from my manuscript for my novel is a breath of fresh air. The deadlines and the prompts are great exercises. It has provided me with feedback, it has shown me where my strengths and are and what my weakness are. It is not unlike going to the gym to work on my weak areas with a "program" to follow.  If you want to sharpen your writing skills I highly recommend join a group and doing a contest. Most require a fee, but usually not very much. There are the groups I subscribe to.

Whimsy:https://www.whimsyfiction.com/

Woodland Writers-women authors group: https://www.woodlandwriters.com/

and my personal favorite

Writing Battles: https://writingbattle.com/battle

My submissions can be found on Writing Battles and Whimsy easily enough by looking up my name-Joyce J Robbins or Joyce Robbins.