A SEO company plays a great role of bringing a website to top from the scratch. Have a look at Black Hat and White Hat SEO practices.
Black Hat SEO
Irrelevant keywords: Using keywords that are not related to your content is a red flag for search engines.
Content automation: Pushing a bot comment instantly is also a bad practice, and although this text contains one or two keywords that will help the URL rank higher.
Fake pages: These are essentially fake pages that are overloaded with keywords that make them easier for search engines to find. Once thses pages are clicked, they automatically redirect visitors to a separate page.
Cloaking: This deceptive strategy involves presenting visitors and search engines completely different content not matching with the URL. The goal is to cheat search engines so they display a URL and user opens it.
Invisible content or links: Another common black hat technique is to hide text or links within your content in an effort to improve rankings. There are some ways to do this, for example adding white color text on a white background, setting the size of the font zero, or to embed a link in a small character.
Note that these are all referred to as black hat techniques and using them consequently will reult into, a site can be banned or penalized with lower rank in SERP.
White Hat SEO
For a better choice, the most successful brands opt for white hat techniques.They use it for search efforts because the strategy focuses more on making your site more visible through quality content and organic link building.
Quality of content: Creating valuable content for your target audience is both worth sharing and worth linking. Your content should be non plagiarised, highly relevant to your niche, and contains no spelling mistakes or grammatical errors.
Effective keyword research and use: A website should focus on a set of relevant keywords, and you can identify the most effective words by researching keywords or phrases you think people might use to find your site. Remember that single words are not always the most effective target. Long-tail keywords are useful.
Relevant Backlinks: If the other sites are linking to your website, it means you have quality content. Keep in mind, though, there are good links and bad links, you want to make sure any off-site links are relevant and offer similar high-quality content.
Internal Links: Linking to content within your own site is a great indicator but try to not overstuff the internal links too. A good rule of thumb is 2/3 links to deep-seeded pages within your site.
Meta Description: Your site's meta description is the first couple of sentences that appear in the search results under your page title, and the best ones are actually written for people.