A run-on sentence occurs when two or more independent clauses are joined without proper punctuation or conjunctions. This can make the sentence confusing and difficult to read. For example, saying "I love to read I go to the library often" combines two complete thoughts without a comma or conjunction. To correct a run-on sentence, you can use a period, a semicolon, or a conjunction. For instance, you could rewrite the previous example as "I love to read, and I go to the library often." Proper punctuation helps clarify the meaning and improves the flow of the writing.