It's the number 1 question I get asked at the end of a successful website project: "Now that I have my website, how do I get ranked on Google?". That is the million dollar question that countless business owners are asking, and unfortunately the answer to that question is as complex and multifaceted as the human genome.
Search Engine Optimization has changed. And then it changed again, and again, etc. I'm fairly certain that Google doesn't like SEO practitioners and has enjoyed thwarting the practitioners time and time again. 10 years ago SEO meant just stuffing your website with as many keywords as possible. Keywords were stuffed in headers, meta data, images, and even invisible text blending with the background. This meant users could be directed to a website that in reality had nothing to do with what they were searching for.
More recently, SEO was about link building and creating random content throughout the internet pointing back to your website. The verbiage of the link was also important, so random links with keyword search terms would appear everyone. You basically paid a SEO company a monthly fee to create random links everywhere, list you in every directory imaginable, and write articles about your website. It was mostly mundane work, so it was outsourced to places with lower cost labor like India, China, and Russia. In 2012 things changed, and anyone using those 'un-ethical' techniques not only lost their rankings, but were also penalized which put them even further behind.
The good thing is that all the techniques I've already mentioned are still relevant. They just need to be used with care without stepping over the line into abusive or spammy. If you do, Google will potentially penalize your domain, and you will lose ranking or get un-indexed entirely. That is why you need to be very careful with whom you choose for Search Engine Optimization. Select a company who is outsourcing SEO to China and using techniques circa 2010 and ye shall be punished.
Modern SEO is about balance between the solid techniques I've already mentioned, but also things you already know you should be doing to market a business. Press releases about keyword relevant news, PPC campaigns to improve credibility and traffic, word of mouth to improve traffic and social sharing, creating fresh and relevant content on your website, people liking/tweeting/Google+ your content, users re-tweeting links that point back to your website, positive reviews about your website on Yelp, Google, Angie's List, etc.
Google's wingspan is wide at this point, and they have very smart people. I would avoid trying to 'game' their system at all costs these days. Instead focus on doing good business, connect with your audience through social media, perform traditional marketing campaigns, ensure your website has the content users are searching for, keep your website updated with fresh content, and make sure people are aware of your successes. Over time, that is the road to success and higher rankings.