Google XML Sitemaps
Jetpack by WordPress.com
It is all in one solution which serves many purpose such as Publicize (Social Sharing Buttons), WordPress.com Stats, Comments, Subscriptions, Spelling and Grammar, Contact Form, Shortcode Embeds, Mobile Theme and many more. WordPress.com Stats can be used to know details about page views, back links etc. Publicize is another advantage which is used to insert social sharing buttons to each post including category and pages.
Recent Posts Slider
This plugin will have a placeholder with featured image of the posts sliding side by side. This make the page to look better and gives professional design which attract more users. There are a lot of configuration to such as to set the size of the plugin placeholder, number of post to slide, sliding duration etc which makes it very flexible to configure based on our need.
Social Sharing Toolkit
This plugin is used to display social sharing buttons which I personally prefer compared to other buttons. This plugins includes more than 15 buttons of various social networking site. There are various option to configure which are used to display the buttons with counters(Like, Tweet etc). There are also Share and Follow buttons which can used along with the normal buttons.
The default setting of the blog will have only Older Post and Newer Post link to navigate from one post to another. But the pagination (page number buttons) will ,give the users better user experience to use the blog. This plugin will add page number buttons/links to the bottom of the page and it can configured to many designs with different colors using CSS.
WP Parallax Content Slider
For any website or blog, the home page is the first thing to concentrate either in terms of design or content. So a banner( logo, images related to blog) can be used to enhance the design of the blog. Even better approach is to use WP Parallax Content Slider which slides images with title of the articles for the given number of post which is configured in the admin panel. This plugin will slide the images with parallax effect.
Apart from using these widgets, there are other small tips and guidelines which can be followed to get better design and content in the blog. You can also improve the performance of the blog using .htaccess (browser caching) file.