Certain rules exist, for using humor while speaking to people.
Firstly, it is important for you, as a person who wants to use humor while speaking to people, to ensure that you use humor (jokes) that the people can understand.
Secondly, it is important for you, as a person who wants to use humor while speaking to people, to ensure that you don’t offend anyone. It is easy to offend people while using humor: hence the need for you to remember to observe basic rules of etiquette, and ensure that nobody’s sensibilities are hurt. This applies particularly well if the issue you are talking about is one that is sensitive. If, for instance, you are talking to a person who works in a supermarket and whose specific job is that of a helper, you need to be very circumspective when trying to figure out what to say. You may say something in a bid to make him or her laugh, only to end converting him or her into an enemy.
Thirdly, it is important for you, as a person who wants to use humor while speaking to people, to ensure that you don’t appear to be trying too hard. Humor that is a result of trying too hard is a real turn off.
One of the hardest things you can be forced to do is to speak with people who are hostile to you.
When speaking to people who are hostile to you, you need to create the impression in them that you respect them, but you don’t fear them.
Further, when speaking to people who are hostile to you, you need to genuinely understand their point of view, and communicate that understanding to them.
Further still, when speaking to people who are hostile to you, you need to be assertive: which means avoiding the temptation to either be aggressive or passive.
Much, of course, depends on the source of hostility in the situation. It could, for instance, be harmless hostility: like where you happen to be having a Gmail versus Yahoo Mail argument, with you arguing for Gmail.com advantages whilst the other people are against the motion. This sort of hostility (if it can be called that) is quite easy to deal with. But it is very different from the hostility in a scenario where you happen to be facing truly physically hostile people, in which case the approach has to be different. So you are advised to deal with hostile situations on a case by case basis, drawing on your knowledge to figure out what the best way to deal with the situation is.
Certain things can hamper your effectiveness when speaking to people.
Firstly, if you don’t appear to be sure of what you are saying, you may find that your effectiveness at speaking to people is reduced. You will come to learn that confidence is very critical, and that what you say is actually not as important as the confidence with which you say it.
Secondly, if you are not capable of reading the people’s body language, especially with respect to their reactions to what you tell them, you may find your effectiveness being reduced when speaking to people.
Thirdly, if you are unable to listen well to people, you may find your effectiveness as a speaker being reduced. It is only through listening to the people that you can start having an idea as to whether or not they actually have capacity to understand what you are telling them. You may, for instance, be speaking about the merits and demerits of social safety nets, to people who have absolutely no understanding of economics or sociology. You may think that you are impressing them with your knowledge when, in actual fact, they are bored stiff: on account of them lacking the capacity to understand what you are trying to say to them.