How to act confidently
Most people feel confident in some situations, but that confidence disappears in other situations. Maybe you feel confident in school because your values are good. However, if you are at a party, you feel like a fish trapped in a net and turns into a shy and awkward. It could be that you feel confident when chatting with classmates, but don't have confidence in the work environment. Whatever the reason, maybe there are some situations that make you feel you have to increase your confidence. Acting confidently is a step towards building self-confidence. You can achieve this by making a number of changes in how you see yourself and how to behave.
1.Look for confident people that you can set an example. Think of people you know who have high self-confidence. These people can be models for self-confidence actions. You can choose parents, teachers, or even celebrities. Observe the person's behavior, speech and body language. Imitate this behavior to blend with you.
2.Smile often and show friendliness. Being friendly to others and smiling makes you look confident. People will believe that you are a happy and happy person who likes to hang out with other people. As a result, they will be interested in being near you.
Participating in various activities will give you the opportunity to be friendly and show confidence.
When you get acquainted, state your name. This action will give other people the impression that you respect yourself and are worth listening to when speaking.
3.When talking and listening, do it right. People who have confidence do not talk too much, make it hard or talk about it. They speak correctly and listen to what others say, involve themselves in conversation according to the prevailing social norms.
4.Have body language with confidence. Self-confidence people usually don't look anxious or nervous. Making adjustments in your body language can show the impression of confidence, even if you feel the opposite. 
Stand with your back and shoulders upright.
Make eye contact when talking to someone.
Don't show anxiety.
Loosen the tension in your muscles.
It is possible to feign self-esteem via non-verbal language:
All these non-verbal indicators will set the tone of the interaction and the interlocutors will see you as having a value higher than theirs.
In the long run, self-esteem is cultivated by seeking oneself. It's a job we can not do for you. Understanding social dynamics can already make us realize that no one is above us and that we deserve respect as much as others.