I love lists, and I'm indebted to Stoney deGeyter for compiling a series of checklists for website marketing ... of which writing web content is an important part, obviously.
Check these out -- paying particular attention to the comments:
The Best Damn Web Marketing Checklist for Website Content
The Best Damn Web Marketing Checklist for Website Content Appearance
The Best Damn Web Marketing Checklist for the Home Page
The Best Damn Web Marketing Checklist for the Contact Us Page