Here is a website that I stumbled upon by chance and thought I must share it with you and keep it here for future reference.
Give it a try ;)
It will improve your writing as it takes you through the process of writing paragraphs step by step.
"Paragraph Punch takes users through the process of writing a basic paragraph. From pre-set writing prompts users develop an idea and write their own topic sentence, body, and a conclusion.
The site provides online interactive exercises that guide users step by step through pre-writing, writing, organizing, editing, rewriting, and publishing."