Regardless of topic, the more time you spend educating yourself, the better off you would be in making smart decisions.
When it comes to SEO, you don't have to be a technical whiz to understand what the search engines look for to help with your website's ranking. Most SEO companies will sell you on efforts that, at the end of the day, won't help you in the optimization of your website.
I was recently made aware of one "SEO Company" whose tactics sounded good to a prospective client, but the work that is being sold doesn't allow for the necessary efforts that is truly needed to help in the website's ranking.
It's not the prospective clients fault, but hopefully over time, education will allow businesses to avoid these tactics some SEO companies sell.
SEO is simple. It is understanding the fundamentals of what search engines such as Google like, and consistently putting forth the effort, based on the understanding of those fundamentals, over time.
These efforts include link building, writing keyword focused content, developing clean HTML and URLs, and networking online. Reviewing analytics and understanding how your users are navigating and finding your site is valuable information. This alone however is not enough, but simply the baseline of reporting.
Don't rely on a company that will simply "submit your site to search engines, install analytics, perform keyword research, submit a site map, etc." These are efforts that are the basics. This would be like a mechanic selling you on how he's going to open the hood of your car. But he's actually not going to do any work on the engine to improve its performance.
Good SEO takes doing these basics, while also formalizing a strategy, based on real data, and carrying through with this strategy over time. If an SEO company says they can do all of this for what amounts to "turn key" type pricing, then "buyer beware". Credible SEO companies charge for their time. Time equates to the efforts needed to perform above board optimization.
Take time to learn more about what it truly takes to do good SEO. Everyone will be better off and your company will be in better position for a greater return on investment.