First of all you need to know what are the services to be done. Who are the people who provide these services. Next, you need to see their experience. Now days, many E-commerce Companies have been formed. They are doing bulk marketing to get clients. They are neither Design firms nor contractor firms. They simply take your projects and sublet to freelancers and other small scale contractors. But to make a home, you need someone who has experience and help you with many innovative designs. Who understands, what does home mean. He will help you to get the execution as per your taste and budget too. Your home can't be done just by looking in to brochures. You have to hire a experienced designer who will guide you from scratch. And, who will always be available when you need. So, decide wisely. Good luck.