I thought I had posted this before; however, when I searched for it I didn't find it.
The University of North Carolina at Chapel Hill has an AMAZING Writing Center. Honestly, it is one of the best in the world. One of the few places where you can earn a degree in publishing.
They have extensive online handouts and now multimedia writing strategy demos that are available free of charge. I use their site all the time when my girls (and their friends) have questions about English for their term papers. I used it last year to learn the way their English teacher wanted them to do Quotations as I had never seen them done in a block style or with a colon before and my daughter kept getting points taken off for not doing it that way!!
I strongly urge everyone who has questions about English, to visit their site:
The Writing Center