Recommended WordPress Plugins – Admin
Akismet checks your comments against the Akismet web service to see if they look like spam or not and lets you review the spam it catches under your blog’s “Comments” admin screen.
Limit Login Attempts
Limit the number of login attempts possible both through normal login as well as using auth cookies.
W3 Total Cache
Easy Web Performance Optimization (WPO) using caching: browser, page, object, database, minify and content delivery network support.
Tutorial link to set up W3 Total Cache http://www.wpbeginner.com/plugins/how-to-install-and-setup-w3-total-cache-for-beginners/
WordPress SEO by Yoast
Improve your WordPress SEO: Write better content and have a fully optimized WordPress site using the WordPress SEO plugin by Yoast.