This minilesson is a great intro or reinforcement for being able to analyze how a semicolon is being used. The sentences used are from famous works of literature, so they are actually used in real life! This activity has worked great for my students, partly because it is easy to adjust the amount of scaffolding I give them.
The file includes an explanation, the worksheet, and a key, all in PDF format. In the explanation there are links to my Google Docs that you could copy and modify.