The best part about SEO is that you can make a change on your website, Google will pick it up within a week and you can quickly see if the change is having an impact or is actually hurting your rankings.
Nobody knows everything about SEO, algorithms continually change, and for this reason you have to run experiments to test different techniques.
When running an experiment, you should only do one major SEO change at a time. If you make 10 changes, you will not be able to tell what’s helping you, or what’s hurting you
When you make a change, you need to give it time, roughly between a week or two. Take the URL of the page that you have made changes to, visit Google search console, enter the URL and have Google fetch, crawl and index it. This way, Google is picking up your update right away, there after you should wait a week or two to see whether you have improved or declined in rankings. If it stays the same, it’s fine, as long as it is not hurting your website
You should also know that many experiments will go wrong… Mistakes may happen. So when you are experimenting make sure that you are constantly checking your Google Analytics, and are specifically looking at organic traffic. If your traffic is going down, then something is wrong, and you need to revert the change right away.
After you revert it, visit the Google search console, and submit the URL to have them index it right away, which will allow you to bounce back right away. It usually takes between 1 to 2 weeks to bounce back.
Once you make a change, that is impactful, you need to keep doing more right away. If it’s not impactful, and you have decreased traffic, you should wait a week or two until you recover before you run your next SEO test. This way you have a solid baseline and are continuously going back to that, so you know if the changes you are making are helping you or hurting you.