SEO is often a task best left to the professional SEO companies. The attention to detail, the number of tasks, and the constant watch of updates that Google slings out all the time makes SEO an full-time job in itself. You can leave the technical aspects to your SEO company; however, there are things you can do yourself that will certainly help you in your SEO efforts.
The first thing you want to do is understand what is going on with your site. There are many analysis tools available that can help you perform a cursory examination of your site and give you insights on how to better your SEO. The number one thing you should do that can help you in your SEO efforts is get set up and registered with Google.
Utilizing both Google Webmaster Tools and Google Analytics can give you insights in to how your site is performing. From within these two tools, you can determine the keywords your site is ranking for, how well it's ranking, your traffic statistics, and so much more. The metrics and information Google supplies you with can be invaluable to pointing you site in the right direction.
The next thing you can do is to add content on a consistent basis. This doesn't mean every day, but just at a steady pace. The benefits of adding content are huge as Google loves fresh content. On top of that, your new content can help your site rank for more keywords and terms, and it can help keep your visitors coming back to your site again and again. All of these will help your SEO efforts while you are focusing on what's important.
Last, but certainly not least, you should focus on your social networking. Though this can technically be considered an SEO task, you don't need specific training or knowledge for this aspect. Your social media updates should be consistent and in line with obtaining the attention of your readers. The benefits can include added visitors to your website and increased business exposure as your followers can easily like and share your content. All of this coupled with the standard SEO benefits can greatly impact your site's rankings.
As stated before, you should certainly hire an SEO company to handle much of the technical aspects of your SEO and internet marketing; however, there are a handful of things you can do that aren't technical in nature and will help you get your site moving in the right direction.