There are some two things that you should always take into consideration when figuring out what to say to another person.
The first thing you should take into consideration when figuring out what to say to another person is that other person’s background. What is particularly important here is that other person’s background in terms of knowledge. Simply put, what you say to the other person should be something that the other person can understand (given his or her current level of knowledge). Otherwise the person may imagine that you are trying to show off: which would put him or her off.
The second thing that you should take into consideration, when figuring out what to say to another person is that other person’s interests. Simply put, if you start telling someone about something that he or she doesn’t have an interest in, you will be boring him or her. You can’t, for instance, start having a dialogue about the deeper intricacies in the process of registering a trademark with a person who has absolutely no interest in business. Sure, the fellow may nod along, and keep on making the appropriate sounds to suggest that he or she is with you, but you will know that, in actual fact, you lost him or her right from the outset.