30 Beautiful (But Simple) Ways To Build Up Your Self-Confidence 

3. Stand up big and tall, but don’t make it look unnatural. Talk loud and clear to people. Let others and yourself know that you have strength and power.

I saw this video once where it said that people who make themselves bigger (literally bigger) before situations where they might seem under confident were able to be more confident if that makes sense. I saw it in a public speaking class one time. For example, before an interview or even before talking in front of a group of people, stretch yourself out, get big, don’t be hunched up in a ball. That would translate to you feeling less confident if you were sitting, bent over all nervous.

I don’t know if that helps, or if it’s what you were asking, but that seems to help me feel confident in a nerve-racking situation.

4. A good fashion sense. I’m a guy and I got a few girls that I’m friends with to help me with my style. It helps a lot. I feel much more comfortable and even some girls have been flirting with me more too. Good fashion ups your self confidence by a lot.