A successful website relies on a few things, primarily, preventative maintenance and regular updates. Keeping a flow of regular, interesting content is important for both your visitors and SEO.

1. Keep your site up to date

Keep your visitors up to date on what you’re doing – this includes news, blog posts, images and all other shiny forms of media. Nothing screams “neglected site” more than a site that hasn’t been added or edited in a few months, or even worse, a few years.

2. Fix bugs as they become apparent

It’s notoriously difficult to get a site to display 100% universally against all browsers and devices in todays age, there is just too many. However, if you decide to browse your site on a different device one day, and notice some things are broken, make a note and get them fixed. Keep hacking away at making the site universally awesome.

3. Preventative maintenance is important

A lot of people, usually in the crowd that doesn’t fully understand technology, simply think that once their site is built, then that’s it. But in truth, that’s what it would be like in an idealistic world.

Cyber attacks are a constant growing concern, so it’s super important to keep all of your site and software up to date. WordPress for example, suffers a couple of major vulnerabilities every so often, which usually does not prove to be a problem if you keep it up to date and locked down.

4. Keep a scheduled backup

A regular backup is important for the rare case that something does happen to your site. Think corrupt database, server failure, or worst case scenario, you got hacked (See point 3 to prevent this)

If you’re using content management, focus on backing up the important stuff: The database. Templates and designs can be remade, but thousands of user generated entries in a database cannot.

5. Treat your site with love and respect

Decreasing the effort you put into your site will definitely show. Take a look at this example for instance. Put in the extra time to do it properly, and you’ll be rewarded by the results.

Wrapping it all together

Putting all of these points into one:
Don’t neglect your site!