Average session duration is a measurement of the average amount of time a user spends on a session. A 'session' is the length of time where a user is actively engaged with a website. If there is a high bounce rate for a particular website, it is likely to have a low average session duration. As the average session duration increases, it is likely that more pages will be visited during a particular session. Average session duration does not measure a website's ability to generate traffic, rather it measures a website's ability to engage users to keep them on a website. This metric is a good indication of a website's attractiveness. This metric ultimately helps to measure and monitor the conversion rate.
The following list provides ideas to help increase the allurement of a website and thus increasing average session duration:
In short, provide strong information about relevant items and display them in an organized way. Try to manage user expectations properly as users who are promised the world but are given sub-par results will quickly leave the page to find another website. The more engaging your content is, the more time a user will spend on your website.