To help you begin to research this topic, here is a link to information on the 20 Most Common Grammar Errors that occur in writing in English from The Everyday Writer:
Visit this site for more information.
Here is a similar list, with 12 Common Errors, taken from The Writer's Handbook:
Twelve Common Errors
Use this checklist as a list of reminders when editing your writing.
- Sentence fragments
- Sentence sprawl
- Misplaced and dangling modifiers
- Faulty parallelism
- Unclear pronoun reference
- Incorrect pronoun case
- Omitted commas
- Superfluous commas
- Comma splices
- Apostrophe errors
- Words easily confused
- Misspellings
Visit this site for more information on those 12 errors.
Finally, this site provides the 10 Most Common Errors that students who are learning English make:
http://www.scribendi.com/advice/the_10_most_common_esl_mistakes.en.html
Choose any one (or two related) grammar problems from any of these lists for your project. You will need to show the problem, explain why it is wrong, show the solution, and provide some practice for the class. You should also have a handout to go along with your presentation. The presentation part should take about 5 minutes with 10 minutes then reserved for practicing the skill and bringing the lesson to a close. Any other videos, visuals, or activities are optional but may make your lesson more engaging.