Confusion between YOUR and YOU'RE - take a look at this video.
Confused about apostrophes? Follow the link to this BBC site and download this PowerPoint
There is a really helpful webpage called 'Punctuation'. It takes you through the basic uses of the different punctuation marks and shows the common errors and how to use the marks correctly.
See the exercises below to practise your punctuation skills.
Follow this link and try the game,
it will help you practise the use of commas.
If you are really stuck for a basic guide follow this link to the Punctuation Pyramid.