A WordPress theme is a way of ‘skinning’ or creating the outer design of your website. The theme can make a huge difference to the presentation and the overall look of your site.

The theme offers a graphical interface via template files. It modifies the way in which the site is displayed without modifying the basic software itself. The theme directory in WordPress offers several different styles and types of themes.

If you have used WordPress, you may have already switched themes once, twice, or even several times. If this is your first time, you need to take care of certain aspects of your site. It is very easy and simple to change themes in WordPress with just a few clicks, but you need to have a checklist of items to take care of before you change the theme. These steps are critical to ensure that everything works smoothly, or you may end up losing parts of your site that you did not intend to lose.

Before making changes to your WordPress theme, it’s wise to take things step-by-step and do it slowly and carefully.

First, change smaller elements to confirm that they are functioning properly. Once you are satisfied, you can start making the more drastic and dramatic changes.

You also need to familiarize yourself with the structure and semantics of the new WordPress theme before you start changing things, so that you can be aware of what you are doing and tackle problems effectively.

Note Aspects of Your Current Theme

You might have made some previous changes using solutions and snippets that you found on the web and added them manually to your current theme. This is done in the form of the functions.php file and as you just made the changes once, you may have forgotten about them.

It is important to go through the current theme file and make note of all the additional code that you have added. It is also important to check out the load time of the current theme, to give you a good basis for comparison after installing the new theme.

Test the load time of the various pages, not just the homepage, by means of tools, such as YSlow.

Backing Up Files

Create a full site backup before you change your WordPress theme – this way, you will never completely lose any file. This is a precautionary measure to be taken for all your theme files, plugins, and any other important database or element.

It is highly unlikely that you would lose them while changing the theme, but you need to be safe.

Maintenance Mode Template

While you are making changes to your WordPress theme, you don’t want users and other visitors to see the site as you’re making changes. The best alternative would be to switch over to a maintenance mode for about half an hour or so, while you ensure that the new theme is well in place and functioning properly.

Remember to set up the maintenance mode and then start activating the new theme. If your site is not yet launched to the public, there really is no problem. If, however, you have a lot of visitors and high traffic, it’s not advisable to allow users to see a broken version of the site.

WordPress offers plugins for maintenance mode and this helps redirect visitors to a maintenance page for a certain period of time. The page can show visitors the approximate time it will take to come back live or you can just give a short message explaining that you’ll be back.

It is a very popular plug-in and it allows a splash page to be added to the blog. The normal message visitors will see is one of ‘Maintenance Mode – currently undergoing maintenance. Try after so many hours, days, and minutes and so on… Sorry for the Inconvenience.’

When you install the maintenance mode, other administrators who are logged in can still access the blog, but you can limit the user type who can.

Testing Plugins

After activating the new theme, you will have to make sure that all the plugins are still in working condition.  Look at all the notes you made in the beginning and see whether there is any functionality from the original theme that you would want to bring back to the new theme.

Test all of the features, such as the search, the single post pages, the contact page and others. Check out whether all the widgets are still in working condition. Ensure that the formatting has not changed with respect to the plugins.

When you change the theme, the new plugins usually use the existing style for display, but these may not always look good or match your new theme.

Check if Your RSS Is Working

FeedBurner is commonly used for WordPress RSS feeds. Default feeds can be connected to FeedBurner and this enables the user to view the analytics on their feed subscribers.

Several themes in WordPress, such as the Standard Theme, the Headway Theme and some others allow the user to integrate FeedBurner while changing the theme. It is important to take care of this aspect and check that the feed is properly directed to the FeedBurner. Failing this, you will not receive any RSS feed for your blog or site.

This might also result in losing track of several current subscribers to your blog or site, as they had subscribed making use of the /feed/ URL. If this is no longer properly pointing to FeedBurner, you will lose them. In fact, they will still be there, but are not visible to you as you cannot see them in the FeedBurner count.

Updating Ads

You might want to update ads and other third party items on your site. For instance, if you are using Google AdSense, you are allowed to format the ads. The best thing would be to customize them to suit your new theme. You could change the color or the size.

For instance, if the previous theme was blue, or you had blue links in Google AdSense, and your new color is orange it makes sense to make changes to the AdSense links as well.

You can also make changes to other third party items, such as Facebook Like buttons, the Twitter widget, and so on. They can be adjusted with respect to size and color in accordance with your new WordPress theme.

Compatibility With Multiple Browsers

After making changes to the theme, check out whether the site can be accessed with different browsers. Different browsers render themes differently, so you need to make sure that the new design looks good on all browsers, or at least the major ones.

It has also been noted that some themes break completely in different browsers, even though they work fine on some. If you think several of your visitors or users use Internet Explorer, ensure that they can access it.

Other things you need to take care of are to check the bounce rate. Some themes work better than others while navigating around the site. Some themes result in increasing your bounce rate and you may want to work on tweaking this aspect.

Conclusion

WordPress has an impressive array of vibrant styles and themes, so there is no excuse for sticking to the default theme just because it does its basic job. Today, it is a lot more than just substance. Presentation and style do count. You need to overcome certain obstacles and maintain a checklist of things that you need to take care of before making the switch.

You need to take a backup of almost everything; database, files, and so on. You can use the Live Preview feature to see the changes before you publish the theme to your site. Also, check out whether the new theme is compatible with all commonly used browsers, such as Firefox, Internet Explorer and Chrome.

Once you make the switch, it would be a good idea to inform your users. You can just write a quick blog post and let them know, and you could even ask them for bug reports. You can ask the audience through Facebook or Twitter and get feedback on the site and whether it looks good on their browser and so on.

If there are any issues, you can ask them to send a screenshot so you can fix it. It is important to get the opinion of different users, as they will have different screen resolutions and browsers. Check out what your site looks like on mobile devices by manually testing the new theme with iOS and Android.

You can also ask the RSS readers to visit the site and see the changes. Try to prune and get rid of anything that you don’t need. While choosing a WordPress theme, choose wisely. Users usually have a lot of advice and suggestions. Communicate with them and start working on improvements. Have a checklist of your own while making any changes to your WordPress theme.

What other things would you add to this checklist for changing your theme? Let us know in the comments below!

Update: As @humpyD pointed out in the comments below, the "maintenance mode" plugin linked in the article hasn't been updated in some time. He also recommended the alternative DP Maintenance Mode Lite plugin.