How do I communicate effectively with other

The effectively communication can be more effective if we can speak clearly. The listener will understood what are you talking about. The first thing is not to talk about something that you don't know. Don't just say it but you must have knowledge about that.
Actually, i'm not a good in communicate but i have a few step that you can follow how to communicate effectively with other. I think the best reason is we must be more confident with our self. If you have that confident maybe it can give point to more effectively with communication.
The others way i will speak clearly when i need to give a presentation and follow the audiens. If the place is bigger maybe your voice must be clearly and loudly and you can repeat again if someone not clear about your present. And then, you must use easy word when need to communicate with other especially with your friends.
The other point is don't always talk about the other person. Its a rude if you are like that. Just be polite when you need to speak with the older person, sometimes they are a deaf but just don't be rude.ok!!
So, if don't want the other person misunderstand what we said, we have to learn how to communicate effectively with other.