Dangling participles (AKA modifiers in this case) rank pretty high on the list of most common writing errors. As a writer, I understand what it’s like. You’re so in the writing zone that in your excitement you forget something from your sentence, a subject for the main clause. Take a look at the sentence below.
Having run back to retrieve the keys, the table was so full of dishes and papers that the keys were hidden under them.
Don’t Make the Table Run
The problem is, there isn’t a person doing anything. This sentence literally means that the table, the subject of the only main clause, was the one to run back. It doesn’t make any sense, since, as far as I know, tables can’t run. Maybe you’re writing a fantasy novel, and the table does run. This sentence still doesn’t make sense because the table wouldn’t have to run back to get something that was set on top of itself. What you need, is a subject that goes with the first clause.
Having run back to retrieve the keys, Harold found them on the table, hidden under the dishes and papers.

Or
Harold, having run back to retrieve the keys, found them on the table under a pile of papers.
Or, you could split this up into several sentences if you want to emphasize the disgusting state of the table.
Having run back to retrieve the keys, Harold searched for what seemed like thirty minutes. He finally found them hidden under something on the dish and paper covered table.
Now, see if you can spot the dangling participle in this sentence.
Having learned to use power tools, my garage got a lot more use after Christmas.
What is the action?
Having learned power tools
What is the only subject we can associate with the action?
The garage
Can a garage use power tools?
No.
But Margaret can! Why don’t you see if you can fix the sentence using Margaret as the subject of the action. I look forward to reading your solutions in the comments.
For more help, check out this post on dangling modifiers over at OWL Purdue.
As always, we’re here to help you out when it’s time to make your final edits.
Happy writing,
Kristin on behalf of the Literary Symmetry team