SEO has not basically changed in over 10 years.
The basics are -
Have content that is related to what the website is about
Make sure your code is valid - html and CSS
Take time to get links to or from similar or related sites
If you have the above then you are on the right track
It then gets complicated when you need to stand out from the crowd and there are plenty of stickies and advice to take you further thoughout this forum but the first rule is get the basics right