Pages must be simple in design. HTML 1.0, non-commerical sites are preferred.
Pages should not use much scripts/css for cosmetic effect. Some might squeak through.
Don't use ads that are intrusive (such as ads that appear overtop of content).
If you submit a blog, submit 1 or 2 of your articles, not your main feed.
If your page does not contain much text, ensure your meta description tags are filled out.
Only the page you submit will be crawled.