Many web developers build a site, hand it over to the client, and end the job there. They never look at what happens once people actually start visiting. However, knowing your visitors' browsing habits is vital to understanding your visitors' experience.

Observe how they browse

The best way to understand your average user is to watch them. Enlist the help of someone you know in the audience - while a focus group is best, friends and family can also play this role. While the site is still in beta, have them sit down in front of the screen and give them a list of tasks to accomplish. Watch them as they approach these tasks and see what they tackle first, how they do it, and if they struggle with any aspects.

Do they try to use the wrong arrows to navigate? Did they make it to a certain page in a way you'd have never even considered? Did they squint at the size of the text or highlight information to read it better?

Ask that they explain their thought patterns on why they did the things they did. It could grant you a greater insight into their browsing experience, and help you pick up on the habits of your average user.

Observe where they go

In the case of already launched websites, look at their previous traffic. Keep an eye out for patterns users follow. Is there a section everyone goes to right from the homepage? Is 80% of your traffic looking at the same page, and then leaving immediately?

First, check for why such a discrepancy exists. Maybe a major forum or news aggregator linked to that page, and the traffic is only temporary - check your referrals. Maybe a link was wrong and pointed to the wrong page on your site - again, check referrals. Maybe first-time visitors come to that page once, but move on to other parts of the site later - check number of repeat visitors.

If you've found that the traffic is normal and they're visiting certain parts of your site more than others very frequently, it's a good idea to focus a bit of extra energy on that page. Add links to other parts of the site they may have otherwise not visited but would value.  Make it worth their time to come back to that page, and make sure they're getting what they want out of it.

Learn from your observations

Of course, nothing you see your users do will be valuable unless you actually apply your new observations to the site. Change your navigation to reflect their browsing patterns. Add more content or freshen content of high-traffic pages frequently to keep people coming back. Link to more content between pages to keep your visitors informed about everything it has to offer.

Most of all, keep your eyes open. Traffic can and will change, and visitors will always be learning and changing too. If you don't keep an eye on them, you could lose focus very quickly.