There are Two Major Types of Search engine optimization (SEO.)
On page SEO:On Page is the Primary form of SEO. This include making sure your website uses all the right HTML tags, structured data to correctly markup your content and is correctly formed or verified. This includes everything the words in the content you use and the code that forms the page. Think of it as: the key points of your page they are known as keywords. You have to use those keyword exactly in your text in order for people to find them. There also something called local SEO, where you know how to identify your business. And lastly the type of design you use, is it responsive? Yes there are even many more factors that need to be looked at, so hiring a professional can save you a lot of time.
Off page SEO:OK, so what does it mean Off the Page SEO? Off the Page is basically about building proper links to your site. You do not have a lot of control, but you have some ability to influence it. You can just pay someone to create backlinks, but in the long run they can hurt you. One method could be, posting articles in another quality site blog & providing a link to your site can help. Or get a similar type business to link to your site.
Just be careful many business get penalized by Google for poor link building practices.
It always best to hire a professional to at least double check you work.