Punctuation allows us to communicate clearly in writing and make the flow of the text xmooth. It has many functions including showing where to pause, separating ideas and quoting peoples words. Using punctuation correctly improves the clarity and impact of your writing. Some of favourite resorces to improve your command of punctuations are:
Purdue online writing lab
Explanations and rules for various types of punctuation.
Queen Mary University
In this series of exercises, the vocabulary for the various punctuation marks is checked, then their function is explored.