This article is very good about increasing adwords quality score http://www.redflymarketing.com/blog/how-to-improve-quality-score-the-ultimate-guide/
Good tips for success from Google: http://adwords.google.com/support/aw/bin/static.py?hl=en&page=tips.html
The landing page quality score portion of QS is all about following their rules and guidelines. It's a go/no-go flag. So if you promote fireworks, which is prohibited, you will get a poor landing page score and nothing you do to your page will change that. It's not about the visual aspect of your page (Google couldn't care less if it's ugly), having an about us or policy page (although those are good to have to build trust with visitors) or anything else physical about the page. It's about the policies. So if you have a poor rating, check the policies to see which you may be violating and then fix.
Quality has no substitution. Its the quality of the content that makes the quality of the page. Get enough back links to make it authoritative.