A question often asked by website owners who employ the services of an SEO practitioner, and a it is a great question.

Before I answer this, let us consider what Google is looking for when it indexes a site.

In a very general way, it is looking for sites that have good traffic levels, low bounce rates , has good links from well ranked sites and plenty of good relevant text.

A lot of the work that needs doing to get a website ranked is technical and statistical and needs to be coordinated, so if you employ an SEO practitioner, let them do all that, that is what you are paying for.

Search Engines like to see relevant links to your site. So if you are a business talk to you suppliers and get them to put a link on their website linking to your website, if there is a trade association do the same. Often times you know and talk to other companies in the same field, get a link from them.
What you must not do, is go crazy about links, getting a link to your site from a Far Eastern gambling site is more likely to do you more harm then good, Unless you are a gambling website, and then it is counted as a relevant link and will be positive.

Use Social Media. There are a lot of businesses who cannot see the benefit, do not forget the old addage “There is no such thing as bad publicity” This is as true to day as ever.
Go on to Facebook, Google+, Twitter and as many of the social media sites you can find, and start pages for your company.
If you are a builder, put up images buildings you have built, before and after pictures, if you sell industrial widgets, tell the world just what these widgets do and what value they are, and include links back to your home site
This will show search engines that how far and wide your reputatation has spread, and give SEO points for it.
A note of caution. Google is not daft, far from it, so if overnight you create many many Social media , and many many blog posts, you will be rumbled and penalised
Neil McVey