On Google alone, there are over 694,000 searches conducted every second, think about that. Search engines consider two main areas when determining what your website is about and how to rank it.

1. Content on your website: When indexing pages, the search engine scans each page of your website, looking for clues about what topics your website covers and scanning your website‟s back-end code for certain tags, descriptions, and instructions.
2. Who’s linking to you: As the search engine scan webpages for indexing, they also look for links from other websites. The more inbound links a website has, the more influence or authority it has.

The search engine considers few factors when deciding what information to show in the search engine results page (SERP):

• Geographic location of the searcher
• Historical performance of a listing (clicks, bounce rates, etc.)
• Link quality (reciprocal vs. one-way)
• Webpage content (keywords, tags, pictures)
• Back end code or HTML of webpage
• Link type (social media sharing, link from media outlet, blog, etc.)

But essentially, there are  3 elements that a search engine considers when determining where to list a website on the SERP:

1. Rank is the position that your website physically falls in on the SERP when a specific search query is entered.
2. Authority, search engines determine how authoritative and credible a website‟s content is by calculating how many inbound links (links from other websites) it has.
3. Relevance is one of the most critical factors of SEO. Besides actual text on your webpages, the search engines will review your website‟s structure, use of keywords in your URLs and what keywords are in the headline of the webpage versus those in the body text.

The more customer centric you are, the better able you are to get good rankings.

On-page SEO:  It covers everything you can control on each specific webpage and across your website, but optimising your on-page SEO is time-consuming, and it is an ongoing process that you will need to take care of for as long as you run your website

1. Implement a good content marketing strategy
2. Update your site frequently
3. Use social media
4. Link to trusted sites
5. Give your pictures, photos, images, graphics a name
6. Interlink your inner pages, link all your important pages from your homepage
7. Optimise your meta description, writing a well thought out, creative meta description
8. Validate your code, insert your website URL into the W3C Validator and it will tell you exactly what code you need to change
9. Vary your keywords, over half of your traffic will probably come from keywords other than your target keyword
10. SEO is not just about which keywords you use on your website, but it is just as much about where you place them
11. Use header tags (e.g. H1, H2, H3, etc.)
12. Do not over do flash
13. Optimise URL’s
14. Optimse title tags: include all of your target keywords; place your keywords near the beginning of your title, not the end, keep your title under 70 characters, create a title with click-through rate in mind
15. Optimise 404 pages

Off-page SEO: It covers all aspects of SEO that happen off your website to garner quality inbound links.

1. Create community in Social Networks
2. Have a blog, this is one of the most powerful ways to promote your company/website online
3. What about guest blogging
4. Submit your news releases to Distribution Services
5. Co-Marketing partnerships are a great way to get inbound links

To complete this post you can also check this out Good content and SEO