But what would be good to put? That depends on your website. Some good points would be for write for us.
• A minimum length.
• A well-ordered article. No one likes clutter.
• A certain level of punctuation. It's hard to be 100% correct, but some commas and dots always works better than none.
• Documentation for what's written - in case of claims being written or facts, always disclose where the info is from.
• In case you allow links to the authors website, make it clear where and how they can include it.