Make sure that the site has a clear call to action. This should not be 'hey look at this cool tool'. Rather, it should be a way for someone to engage in a meaningful way on the issue being presented.
Some examples:
Join a mailing list (which means you need to create one)
Attend an event
Share on Facebook/Twitter
Donate to a particular organization
Create a Tumblr for people to share interesting findings (if it's a data access site)
Web Search Indexing
If you have a staging site, tell the search engine robots not to index you with a robots.txt
Make sure you allow indexing when you are ready to launch
Make sure you handle the www subdomain with DNS redirect
If your site relies on a database or server-side code, it should use caching and be load tested. If it's a static HTML or Jekyll site, you can skip this section.