While every writer has a blind spot, run-on sentences are squarely in my field-of-vision. They drive me crazy. While the length of a sentence may flag it for further inspection, a run-on is any sentence where independent clauses meet incorrectly. Here’s a short article that describes the most common errors. I’ll add a fourth way to resolve run-ons, though: If you’ve written two sentences, think about letting them stand as two separate sentences. Insert a period, and you’re done. Easy as pie!