The first thing you need to do before getting in touch with an SEO firm is to be crystal clear about the requirements and goals you want to achieve with the help of SEO. Then you can ask the SEO firm about their previous experience and work done. You can go through their reviews and testimonials. You can even get the estimated cost of operation so that you can check it with your budget. After answering these basic questions, you'll be able to filter out if the SEO firm is the right fit to handle your business requirements.