The first step to hiring an SEO EXpert in Chennai like me is to search for them on the Internet. Get the date by analyzing their website. Before hiring, have a meeting with them (preferably face to face) and talk to them to see how much they know about their field, their experience, and other details that might help you understand more about them and their process.
Talk to some of their clients and get feedback on how they are professional. Conduct an audit with them as well, and if they happen to check all your boxes, hire them.