I was not an early fan of CMS systems. I spent years learning HTML, CSS, etc. — so they always kinda seemed like cheating. I eventually came around and decided I should commit to one of the top three and WordPress seemed the best fit for the type of sites I build most often. It was a great mix of simplicity, extendability and customizability. One of the things I love most about WordPress is the ability to use plugins to extend your capabilities.
At current count there are more than 45k Wordpress plugins, with over a billion downloads between them. The capabilities of these plugins are almost limitless and most are either free or low-cost. I could write a thousand blog posts and never scratch the surface, so instead I will concentrate on my three favorite.
The plugins one chooses are often different depending on the site design and its needs, but I have a couple I use on nearly every site and one I just started using that's simple but extremely useful.
Proving that simple things are often the best, Duplicate Page does exactly what the name would suggest — it duplicates a page. Why is this so useful? Typically when I build a WordPress site, I start by developing layout templates for various sections of the site, then I go in and create them within the site's theme. Duplicate Page adds a "duplicate this" link to each of your pages and posts, as well as a duplicate button to your admin nav. Once clicked it simply duplicates the current page to a new draft. It's really simple but it saves a ton of time. It's great especially for pages that are very similar like job postings or employee bios. This is probably the one plugin I use every time I am editing a site.
Yoast is by far my favorite SEO plugin. It comes as a free or premium option. The free version takes takes a lot of work out of SEO tasks. It allows you to easily add meta descriptions to pages, focus keyword, and snippits. It also preforms page analysis that checks for proper SEO best practices and readability. It has a simple red, yellow, or green alert system on each page and post that allows you to see at a glance if your pages are properly optimized. You can also create and manage xml site maps. The premium version adds more functionality including multiple focus keywords and a redirect manager for only $59, a price I would gladly fork over even for the free version.
Sticky Menu (or Anything) on Scroll
Getting back to the category of extremely simple, this is another plugin that does exactly what the name says, it allows you to choose any element on your page and make it stick to the top when you scroll. It works great for menus, but it's also great for calls to action, ads, or anything you want to keep on screen no matter how much the user scrolls. It also allows you to shut off the element on smaller screens. The only real issue I have with the current version is that you can only make one element sticky on the site (the FAQ states this will be changed in the next major update).
There is, of course, a time to use plugins and a time to custom code, but I find it's best to search for a plugin that can save countless hours of coding when appropriate. Too many plugins have a tendency to slow down the load time of your wordpress site, so be sure to not go too overboard.