I have learned a lot through this forum over the years. I thought I would try to help out a bit and hand out some free advice. Remember advice is worth what you pay for it though... :-)
G has been refining their algo as we all know. This happens constantly, but there are some points that are pretty clear. Taking advantage can help, and not addressing can hold you back.
1. Mobile friendly. Yes, WP ad other CSS has moved to mobile friendly by default. However, did you know that G has moved to mobile index? i.e. mobile index. Now is the time to make certain you are mobile friendly. If you are not, you are gong to drop in the index and there is nothing you can do about it. G even has a tool in WM to test your site.
2. Linkless SEO. I have been doing this for about 4 months as an experiment. It works really well. So in addition to my PBN network which I have mentioned in the past, I do a lot of brand building now. My idea was to vastly inflate the content and audience for my brand. Not to drive traffic or seo via links, but rather the theory was that the cloud of content would create value without any links. The answer is, it does, big time. And the beauty is that there is ZERO risk as you are not linking to your MS. Turns out G now associates mentions and linkless content as a link. :-) And SER is the perfect tool for this strategy.
3. Featured snippet. Do any G search. Top of the page are featured snippets. Grab a spot and conquer your seo. Adding structured data in your code can get you one of these crazy valuable potion zero spots.
4. Voice search is exploding. Long tail kw's are typical of voice.
5. https G has clearly mentioned that they prefer https on sites and are going to punish publishers in 2018 who are not https. Very easy fix.
Hope some or all of this helps.