Dr. Grammar - Frequently Asked Questions site will provide you with some tips regarding usage rules. You might find the rules and examples helpful for online tutoring, and you might want to print some of the information for in-person sessions. In particular, students are likely to find the quick rules for comma usage helpful. The site even suggests printing the comma usage rules, laminating the paper, and keeping the sheet handy at the computer. Dr. Grammar is Dr. James HiDuke at the University of Northern Iowa, and he grants permission to teachers and students to copy his rules. Here is the link to the grammar page of his site. Other parts of his site can be accessed from this page: http://www.drgrammar.org/faqs/
