Absolutely spot on comment. That, as far as I am concerned, sums up the process! There are so many things for which Google will penalise you - anything that may be deemed spammy, for example. And bad SEO often involves techniques that, in the long term, will really serve as a detriment to your site.

You mention hiring experts and, I have to say, I agree entirely. Unless SEO is something you have literally hours and hours to spend on every week or something that you’re simply passionate about, you won’t be motivated to keep up with the changes and talk around the ever changing algorithm - which ultimately means you could end up employing tactics that will put you in a worse position than before you even started doing any SEO!