Punctuation (SAS leaflet)
Advice leaflets originally produced for the Study Advice Service in the University of Hull, which holds the copyright:
Essentially, punctuation is a guide to reading aloud. Each punctuation mark represents a pause, or a tone of voice. If you are unclear about punctuation, read your text over aloud - or at least move your lips. Where you think a reader should make a major pause (draw breath), use a full stop. Where you think a reader should make a smaller pause, use a comma.
If you do this, you will rarely be wrong. You will not be using punctuation in a very sophisticated way, but you'll probably have made no mistakes.
Sometimes, the use of reading aloud can help you decide whether you need a comma or not.
Warning: many academics disagree about commas. Where Dr X thinks a text needs commas for clarity, Prof. Y may feel there should be fewer commas. Some people use much more punctuation than others where they want to make their meaning, or chain of argument, clearer. But a good deal of punctuation is A MATTER OF TASTE. (It's also a matter of style - of a writer's individual choice.)