Unfortunately for many of us, rigorous grammar exercises and diagramming sentences have fallen into disuse in many educational institutions across this country. Consequently, many of us struggle with where to put our commas and semicolons as well as apostrophes and question marks. However, knowing how to punctuate your writing correctly is important. Your writing represents you to countless readers of memos, emails, faxes, and reports, to name only a few. Faulty construction and misplaced or nonexistent punctuation tells your reader that you are either careless or ignorant of the rules of grammar.
The best place to correct your mistakes comes in the handy form of the Prentice Hall Handbook For Writers. The index often provides the quickest route to the problem. Once you know, for example, that you are a "comma splicer" then you can do the exercises in the handbook to overcome this barrier.
Guide to Grammar and Writing is an online aid for correct grammar and punctuation use. Here you can take quizzes (without penalty!) to ascertain your level of comfort from sentence-level grammar to dangling modifiers. This link also provides exercises for those of us who are "grammatically challenged" to access more information online about grammar and punctuation use.
If you would like to submit a grammar question online, visit the student portal.