A good way of describing someone is by telling their appearance. Talk about how they look. Are they tall or short? Plum or healthy? What is their hair color? Do they have straight, wavy, curly, or frizzy hair? For men, do they have a mustache or a beard? Physical appearance is an easy way of describing someone.
Describing by character means telling others who they are on the inside. In general, people are kind, mean, friendly, generous, or ruthless. If the person shows respect to everyone, they are polite. You can describe their intelligence as well. Are they smart and clever, or not too bright?
You can also describe their personality type, i.e. introvert or extrovert. There are various ways of describing through character. If you are a writer, you should focus on three main character qualities to start with character development.
People’s feelings are always changing, but you can tell how someone feels based on their mood and behavior. Some of the most common feelings are - happy, sad, mad, angry, stressed, relaxed, exhausted, and bored.
The answer to this question really boils down to the context and why you're describing someone. For instance, if you're just describing, let's suppose, your boyfriend to a friend, it's pretty easy. But, If you want to describe some personality in an essay, you have to look for the right words. There are thousands of adjectives you can use in different contexts. Play around with words until you feel like you appropriately reflect who the person is and what they do in a positive manner.
Someone’s mannerism is the way they act or speak. Do they touch their hair while talking? Do they move their arms a lot while speaking? Do they bite their lip? These are personality quirks and manners. Other such examples are rubbing their hand on the back of the neck when they are thinking hard or rolling their eyes when they are sarcastic.