When starting a blog with WordPress, choosing the right plugins can make all the difference in creating a functional and engaging website. Here are the Top 5 Essential WordPress Plugins every beginner should know:

1. Yoast SEO: This plugin is crucial for optimizing your content for search engines, helping you to increase your visibility online.
2. Akismet Anti-Spam: Protect your blog from spam comments with this powerful tool, ensuring meaningful interactions on your posts.
3. Jetpack: Offering a suite of features, Jetpack enhances your site's performance and security, providing analytics, social sharing, and downtime monitoring.
4. WPForms: Create user-friendly contact forms easily with this intuitive plugin, allowing visitors to reach out without any hassle.
5. MonsterInsights: Easily integrate Google Analytics into your WordPress site to understand your traffic and audience behavior better.

Customizing your WordPress theme can dramatically enhance the look and feel of your website, making it unique to your brand. To begin, access your WordPress dashboard and navigate to Appearance > Themes. Here, you can choose a theme that aligns with your vision. Once you've selected a theme, click on Customize to enter the WordPress Customizer interface, which allows you to modify various aspects of your theme, including site identity, colors, menus, and more.

To personalize your theme further, consider following these steps:

1. Change Your Site Title and Tagline: In the Customizer, locate the Site Identity section to input your site title and tagline.
2. Adjust Colors and Fonts: Explore the Colors and Typography sections to refine your site’s aesthetic.
3. Add Widgets: Navigate to the Widgets area to add desired functionalities to your sidebar or footer.

If you're a WordPress user, encountering errors can be frustrating. Some of the most common WordPress errors include the infamous 'white screen of death', error establishing a database connection, and 404 page not found issues. Understanding these problems can save time and enhance your website's performance. For instance, the white screen of death often results from a memory limit issue or a faulty plugin. To troubleshoot, try deactivating plugins by accessing the WordPress dashboard or through FTP, and see if the issue resolves itself.

Another prevalent error is the 'error establishing a database connection'. This indicates that your site cannot connect to the database, which might be due to incorrect database credentials in the wp-config.php file. To fix this, double-check your database name, username, password, and host. Lastly, if you encounter a 404 error, it typically means your permalink structure needs updating. You can resolve this by going to Settings > Permalinks in your WordPress dashboard and re-saving the settings, which refreshes the permalink structure and often resolves the issue.