When looking at user analytics, there are thousands of data points we can use. User analytics are generally intended for the marketing department, and we are only going to look into them for a couple of fundamental metrics. Even at that these aren't always going to be extremely clear on their performance implications
First, the most helpful metric is the number of times someone uses a page. As mentioned earlier, by evaluating page views you will get a sense of where inside the application people are going. If you know where users are going, you get an idea of how important it is that a page should be optimized. If the landing page is viewed five times as often as any other page, it makes sense that it is worth spending extra-time on optimizing it.
There are other ways to take advantage of page views. These different ways require a deeper understanding of your application and its flow, but they can indicate potential issues which are occasionally related to performance.
So the idea is to look and see if there are sections of the site where people are expected to go but don't seem to be. Remember to take care with this approach as more often then not there is something else keeping them from the page, such not seeing the link or not understanding why they should be going to the page.
Exits are a pretty simple metric. It is the location where your users are leaving the application. With the exits statistic, you need to know where people should be exiting your application and you look for pages where they exit unexpectedly.
There will always be some exits from any page. Unlike, developers crazy about efficiency other people have lives that occasionally intrude on their use of an application. However, if there is anywhere, that seems to be higher then expected we can look to see if a performance issue is frustrating users, again this could be any number of the other problems so use it as a starting point and as validation that there may be something worth fixing.
Another thing to keep in mind is that if the exits are happening from a multi-step process, the major problem could have been from an earlier step, in particular, check the immediately proceeding step.