Here are a few great links
The New York Times series of writing lessons, starting with the basics and leading to more advanced techniques.
Cool verbs, my favourites are – micawber, pule and tyro.
More cool verbs.
Homophones – words that sound alike but are spelt differently with different meaning.
Punctuation marks?!! Use them, don’t abuse them.
Oh and look at the lovely magazine I got in the post today. I love everything about Inis Magazine.