How to increase DA of a site which has plenty of sub-domains? I know that sub-domains are considered as separate sites, so how?
Moz DA is a third party thing. Building links to all sub-domains will increase the overall DA of the site no matter what search engines thinks about sub-domains, as separate sites or not.
DA will improve when you receive good Searches through Search Engine Like google and more majors search Engine.
Looking for Increase DA Instantly then you need to Run Adword that will provide your website Quality Paid Traffic through Search Engine or Organically Improve your Keywords Ranking this will automatically improve your DA
Get quality content, do daily social activities, Building a strong branding
Good on page
Good traffic
Social signals
Quality links
low loading time
To increase DA of your site follow the following instructions:-
1 Good on page SEO
2 Better link building technique
3 High pr backlinks
4 Good traffic
It will take time to increase DA by optimizing the website pages to improve performance in the web.
when you get good backilnks and work on high PR sites.
Basically DA depends on quality on page seo and number of quality backlinks.