Note: To avoid starting the battle over article length, I believe there are two methods: Shorter articles to get traffic quickly and longer (800 words+) articles for residual traffic that get republished. You have to ultimately make your own decision.
Keys to Writing an Effective Article that Converts
• Make sure that your title is interesting and engaging: '3 great ways to make your own free dog food' is better than '3 recipes for dog food'
• Keep paragraphs short and easy to read! 5 sentences at most for a 400 word or less articles, this will give the reader an impression that your article is easy to read
• Try to create a 'slippery slope' with your article. This means ending each paragraph in a way that leads the reader into the next paragraph. Ways to do this include ending a paragraph with a question (are you ready for the next step?) or hinting at something in the next paragraph.
• Make the article easy to read! If it's a list style article, use numbers and bold the sub-headings. Separate paragraphs where it makes sense and make the article as clean and organized as possible.
• Read through your article when it's done. Does it deliver on the title? If not, start over. If it does, make sure that there aren't any mistakes and that it flows well.
• Always put quality information, and always leave about 25% out. The idea is that they'll like your article and will click through for the rest of what they're looking for.
• Try to make your resource box blend into the rest of the article as much as possible, and always mention the benefits of your freebie in your resource box.
Hope it helps, please share any tips that you have!