It can be hard to explain to someone what you are feeling and what you need from them but it is so important to learn how to do this in your friendships and relationships. Oftentimes we expect others to know how we feel and to understand. We want them to know what is wrong and how to help without us explaining it. However, this is not realistic and we need to stop putting these expectations on others.
For example, if you are upset with someone for something they said or did, you should be straightforward with them and explain what it is that they did to upset you, why it upset you, what they could have said or done instead, and how they can fix it. I have found this to be very helpful, especially in my relationships. I realized that people cannot read my mind and it helps significantly when you are honest with them. It can be difficult or even awkward at first but in the long run it helps everyone in the situation. Try processing your emotions first and then expressing them to that person!