Grammar #10

Commas are an essential tool for any writer. They are both useful in the flow, and help to show the bodies of a sentence. Use commas to separate independent clauses when they are joined by any of these conjunctions: but, or, nor, for, and, yet, so. I like to think of them in this order as saying "bonfires". Also, use commas after an introductory phrase or clause.
Clause: "While I was studying, someone knocked on my door."
A good way to help remember when to use a comma after a clause, is looking for their common starter words; after, although, as, because, if, since, when, while.
Introductory phrase: "Having finished eating, I got up and left."
There are also a list of common starter words. To name a few; although, well, however.
The use of commas is essential in English, as well as Latin based languages.

This site was fun and easy to understand, and really helped me to understand a lot about how a comma works

http://owl.english.purdue.edu/handouts/grammar/g_comma.html