Dr. V's ENL 111 and 121
The Psycholinguistic Model
Most comma splices and run-ons appear where professional writers would use semicolons, colons, or dashes. If you want to study this more, click here for instructional material. You can also find exercises and answer keys here. Be careful, however, don't use these three punctuation marks unless you know what you are doing.
Sentence Errors [ppt]
Henry Canby's Explanation of the Rules of Punctuation [MS Word]