Things you should avoid:
Try tactics that promise “instant” results. Most of them don't work or work in the short term for a couple of months, after which things end very badly. There are some tactics that can be effective, but they also go against search engine terms. In the SEO industry they are called “Black Hat SEO”. The risks far outweigh the benefits of using this tactic, and search engines ALWAYS detect them.
Stay away from things like private blogs created just to sell links, link exchange services, automatic promotion services, temporary (rental) links and other similar things. SEO is, first of all, working on the quality of the site; the “Loot” button does not exist in it (as in any other marketing area).
Search engines are constantly updating their algorithms. Things that worked 10 years ago probably won't work today. Many optimizers use outdated promotion methods that were relevant in 2010-2014, but no longer work now. Be sure to double-check information in several sources before implementing something on your site, if it is not basic things, as in this article.
Help is needed? Qualified AVSEO specialists will be happy to help you optimize your website.