What kind of analytics do you perform and what do you look for?

Google analytics
See your most important analytics data first.
Find out which online campaigns bring the most traffic and conversions.
Determine where your best visitors are located.

See your most important analytics data first. ...
Find out which online campaigns bring the most traffic and conversions. ...
Determine where your best visitors are located. ...
Learn what people are searching for on your site. ...
Visualize what people click on the most. ...
Uncover your top content. ...
Identify your worst performing pages.

5 Red Flags to Look for in Your Google Analytics Data
Low Time On Page. Time On Site is a key metric that you need to look out for when analyzing your Google Analytics account.
High Bounce Rate.
High Self Referrals.
Low Website Visitors to Leads Ratio.
Low Number of Visitors.

I prefer as per situation which parameter is required