Whilst the new year is often a time to make resolutions, we don't advocate that - you'll only break them anyway!  
However there's no better time than now to do a bunch of those little jobs that fall between the cracks during the rest of the year.  We're really concentrating here on managed switches.

Document your configuration
Consider annotating your switch configuration, most support it, and it will ensure that those more obscure VLAN's still make sense when you revisit them 6 months later.

Naming prevents mistakes
Give your switches sensible, descriptive names.  When you've only got 2 switches on your network this seems unnecessary, but as the network grows connecting to the wrong device accidentally becomes a real possibility.  Seeing that name at the console might well save you from disaster.

Backup, Backup, Backup
Backup switch configurations.  We tend not to think of these silent workhorses of our networks that much until something goes wrong, and you don't want to be in the situation of having to recreate a configuration from memory after replacing deceased hardware.

Update firmware with care!
Whilst you might keep your operating systems regularly updated, network hardware often gets overlooked.  Yet it is important to remember that such devices can have vulnerabilities and particularly those at the network edge should be kept up to date.  What we don't recommend however, is simply upgrading to the latest version for no reason.  Check your with either your vendors support site for vulnerability reports and fixes for example Cisco provide comprehensive details on their Security Advisories site.  Alternatively there are third parties such as the Carnegie Mellon Emergency Response Team site which aggregates advisories and vulnerability reports from multiple sources.