This is not the sort of question that can be answered effectively by another person. For example, my communications tend to be with students, my children, or my wife. You, presumably, have none of these and so my answer would not be useful as a model for your own. Let us, instead, look at how miscommunications might occur. We can then think about how this might apply to situations from your own life.
One way that communication can be ineffective is if one of the people is not really paying attention. If you are not paying attention, you might miss words or you might miss body language or other nonverbal cues. This can lead to a situation where you do not understand the other person properly. This lack of attention can be caused by a lack of caring, but it can also be caused by things like stress or being busy.
A second problem can be if people use jargon. If a person uses technical terms when speaking to another person who does not know those terms, misunderstandings can arise.
Another way that communication could be ineffective is if the two people are from different cultures. The two people might have different underlying assumptions that make them understand the same conversation differently. For example, one person might think that the other had been agreeing to do something while the other person had actually been politely saying “no” without coming out and explicitly saying so.
It is also possible to misread body language, especially across cultures. Some cultures think that looking in another person’s eyes is disrespectful whereas Americans see it as evidence of sincerity and of paying attention. Misunderstandings like this can reduce the effectiveness of communications.
Perhaps you could try to think about communications problems such as those mentioned here. Think about situations that you have been in that might have included problems mentioned here.