If Google can’t crawl your website, simply your website is not going to rank. For Google to crawl your website you need to provide your sitemap.
Your WordPress website permalinks should be short and simple with your post keywords. This is one of the most common SEO mistakes that new bloggers make.
Incorrect headings is another one of those common SEO mistakes that many new bloggers make. Good thing is that this mistake can be easily fixed.
Every image you upload into WordPress gives you the option to add Alt-text. If you want to optimise your WordPress websites SEO, you should write alt-text for every image you add.
As you can see, there are a lot of reasons your websites SEO could be bad. One of them is image size. Image size heavily affects your websites load time.
Plugins are great and they make bloggers life much easier but if your WordPress website has plugins that you are not using - remove them.
For your WordPress website to function properly you need only your active theme and latest WordPress default theme just in case.