If you're interested in a good starting point for Search Engine Optimization, I wrote about that a couple of years ago and it's all still relevant today. The bottom line is that we write our code, and the software that you'll use to create new content, for optimal search engine findability. I don't typically make a big fuss over this, as I'm simply following industry-standard best practices. Technically well-formatted code is the minimum starting point for a good website.
The smartest thing to remember about Google and all of the major search engines is the depth of resources that they put into their core business. Google is a company that provides free wifi to the entire city that they're located in. They have their hand not only in every corner of the internet, but also in Virtual Reality, self-driving cars, cartography, and the list goes on.
And their core business is their search engine.
They have thousands of engineers whose sole purpose is to tweak the algorithms to ensure that when somebody 'googles' a question, they receive the correct answer. We need to assume that they're smarter than we are when it comes to search. With that frame of reference, you know the "secret" to finding yourself on the coveted first few search results:
Your website should contain the authoritative answers to the questions your customers are asking the internet. There is no shortcut to actual relevancy to your potential customers.
Many people who sell Search Engine Optimization services will start by asking you what your main keywords are, or what you want to be found for when your customers are searching. This is a great place to start, so go ahead and make that list. Then make sure you're talking about that thing on your site in a way that's engaging to real people. Talk about the things you want to be known for. Make a tutorial video about your specialty. Create relevant content that is tangential to your services. For example, if you sell propane tanks publish some of your favorite summer grilling tricks.
Write with authority, and write often. Then, share your blog posts on social networks so that your efforts are seen by your real customers. Watch your traffic to see what topics are the most successful, and hone your craft. Watch your social networks meticulously, interact with your customers there, and make sure to answer their questions in a timely manner if they begin to use those tools to ask specific questions.
In short: once your site is built on a solid technical foundation, evaluate your "static" content to make sure you're talking about things relevant to your customers. Set up the social media channels where your customers are looking for you. Write in your blog, then be as extroverted and enthusiastic as possible about sharing with all of your social networks.
Create valuable content, re-evaluate based on your site analytics and actual ROI, repeat.
A note on analytics
As with any marketing effort, gathering real data on ROI is tricky. How do you measure the effectiveness of a billboard or newspaper ad? The people who sell billboard and newspaper ad space will have impressive numbers that quantify the amount of people that see your ad, but your customer base may or may not respond to that type of messaging in a way that helps your business grow, and it's up to you to determine the effectiveness of those mediums for your business. The same thing applies to your web-based marketing efforts.
The way to measure any marketing effort is to set a goal, gather data before you start the campaign, then gather data during and after the campaign. On the web you have access to free analytics tools that make it very easy to see your traffic spikes. Traffic reporting is useful to an extent, but that metric gives you the same type of data that a billboard company provides by counting cars in a busy intersection. So don't focus too much on that number in isolation. For example, if you buy Google sidebar ads, you'll likely see a large increase in traffic, and also an increase in your "bounce rate." Bounce rate is a measurement of "quick nopes" – people who come to your site and quickly realize it's not what they're looking for. Though an increase in traffic is certainly the goal, make sure you're keeping an eye on the type of traffic you're receiving. Monitor the geographic location, time-on-site, and referral links (What they searched for to find you, or what social networks they linked from.) Then monitor the campaign's effectiveness, adjust as necessary, and repeat.
There is no silver bullet
I hesitate to say that my side of things – the technical accuracy of the code – is easy, but at least it's much more binary. I've either done it correctly or I haven't, and most of the time it only needs attention during the initial site development. The real work is time-consuming and requires nuance and persistence. The best advice I can give is to be realistic about how much of your time you can afford to spend on writing engaging content and monitoring results. It's possible to do a great job with this on your own if you're a good writer and have a knack for connecting with your customers in a natural way. If you're comfortable with your 'voice' being the voice of your business, by all means give it a shot. But in many cases a good marketing consultant is worth the investment because they don't have a hundred other responsibilities in your organization and they get to focus on meeting a particular set of goals for you. They'll get to know your customers with fresh eyes and help you learn new ways to connect with them based on their experience consulting for dozens of other companies. Their job will be to meet your marketing objectives, and they often succeed. But even if they fall short of the goals that you've set together, you will have learned something about your customers in the process, and it will be time and money well-spent.