1.Keywords in <title> tag 2.Keywords in URL (EG:- here is ugly url yourwebsite.com/okdpkfsdpf.html) HERE SEO optimized yourwebsite.com/yourkeywordshere. 3.Keyword density in document text (maximum 5%). 4.Keywords in anchor text.(Put your keyword rich anchor text at the time of blog commenting, forums signature's, directories, Press release, article marketing, Guest posting.) 5.Keywords in headings (<H1>, <H2>, etc. tags). 6.Keywords in the beginning of a document (In the first line (Recommended or in second or third line. Bold your keywords.) 7.Keywords in <alt> tags (Images). 8.Keywords in metatags. 9.Links from similar sites (Your site niche). 10.Links from .edu and .gov sites. These are few more.But SEO not ends here.
You can look at the google SEO report card for clarification on your checklist points; it has some good reading material for anyone looking to brush up their SEO skills; http://googlewebmastercentral.blogspot.com/2010/03/googles-seo-report-card.html
If someone has keywords in domain name and Links from the pages with PR, then these are the plus points.
After on-page optiimisation process, it is always better that you get the pages verified and analysed on the tools available online for meta tag anaysis and keyword density. This ensures that there has been optimal and proper use of the keywords in the meta tags and the relevance of the above tags to the page content is also as expected.
You may want to take a look at SEO Power Suite and download the free version. Run their Website Auditor against your page and you'll get more insight than you would believe. This should help to round out the above list when you see the number of critera they check.