I wonder if doctors get so many doubts about medicine as I get about writing! Maybe because it is my profession, I am constantly looking for tips or pointers for improvement. Despite writing day in and day out, I am sometimes stumped about where to break a paragraph, or when to use a semicolon and not a full stop, and many more such seemingly trivial (but certainly non-trivial) doubts.
I almost jumped for joy when I found this link on Lifehacker. Roy Peter Clark provides us with 50 wonderful tools/tips for writing better. Whether you want to learn when to end a sentence, or how to retain readers' attention, this is the resource to check out.
My favourite was "Writing Tool #23: Place Gold Coins Along the Path"
Also visit www.poynter.org for a lot more resources on all forms of journalism.