I've seen companyies spend thousands on SEO for very common things that could have easily done by the site owner. It's a waste of money for hot air blowers. There are tons of information on the Internet what really counts, e.g. having great, unique content and <title>...</title> tags that contain the most important keywords that match that content on a page, having the site well structured and simply using Google Search Console to find out what Google thinks about the site. Learn some basics once, apply them and you are good.