In theory, WordPress is just another way of putting your website online. So, in theory, SEO for WordPress should be subject to the same rules that apply elsewhere. And, to an extent, that's true. But there are some subtle (and not so subt) differences that you need to be aware of to make sure that your WordPress site is as well optimized for the search engines as it can be.
WordPress itself has the ability to be extended with "plugins" that hook into the heart of WordPress and allow you to do almost anything with it.
If you have not already done so, you should install an SEO plugin.
There are a variety of these available but the market leader currently is the one from Yoast, simply called WordPress SEO. It's well supported and regularly updated, which are both very good signs especially for something that you're going to be trusting your online success to.
Once you've installed your SEO SEO plugin, you'll notice that a number of extra boxes appears on the places where you add posts or pages to your website.
The order of these boxes will vary according to your chosen plugin but they will include:
There will also be other options – maybe hidden in an "advanced" section – that will tell you other things and allow you to easily fine tune the way that your WordPress posts and pages show up.
It's worth exploring those other options, even if they seem daunting at first. There are plenty of tutorials around that will help to explain anything that does not initially make sense. But because most people do not delve that far into things, it's usually safe to leave these at their default settings.
As far as plugins go, that's probably all you need to do.
The other things that need to happen are the same for WordPress as they are for any other website: making sure that your page content is good quality, that you update your site regularly, etc.