Clients are always looking for perfect and best product, First be confident enough and believe on your product, because how you will be successful to sell your product to the client if you are100% a believer.
secondly: emphasize the strength, benefits of your product, state the uniqueness of your product and how it is different from the other. don't give wrong information t. Be honest for what you know and you don't know, are only human you don't know everything. If client want to test your knowledge about your product answer it with honesty and correctly. Be humble enough to accept constrictive criticism to improve your skills. this is my point of view base on my experience.
