If you do not have every element of a citation include as much information as you have. Remember that URLs and DOIs do not have a period after them if they are at the end of the citation.
Websites with no named author
When the responsible organization for the website is not part of the website's name, include the organization before the name of the webpage.
Author AA. Blog post title. Blog Name blog. Month Day, Year. Accessed Month Day, Year. URL
Twitter Handle. Post content. Month Day, Year. Accessed Month Day, Year. URL
Entire database without an author
Entire database with an author or group author
Single entry in a database