Actually SEO is time taking process and ranking position depends on many factors like competition, age of the domain, on page, off page, and other SEO practices. We always tend to follow all rules & guidelines of search engines so that we can sustain the achieved results for long time. We do not trust on bad practises like black hat SEO or grey hat SEO which some SEO agencies use to bring fast results, but these practices are not good for long term and sustained results.