If you want to efficiently understand how your potential clients are searching for the products or services you are offering, Keyword Research is critical.
The keywords you are using for your site are possibly not the ones your potential clients are using to look for your services.
Good keyword research starts with gathering data: keywords currently bringing traffic, keywords with impressions but no clicks, ppc data if any, keywords used by competitors, Keyword tools
Voice Search is creating a lot of disruption in terms of keywords research since people use different phrases depending on whether they type of speak. In general voice search keywords are longer and they are in the form of a question.