My friends comment that i usually seem confident, even when in at times i'm not quite that inside.
My advice firstly would be the way you walk. Stand tall, don't hunch, step lively, don't drag your feet, as i see a lot of people do. Sort of march, yet not.
Another thing is your whole mindset. Know who you are, and accept who you are. Lots of people think they can be confident only when they think they are incredibly great or something. What i say is, you know what your strengths and your weaknesses are, and you know that both define who you are, and the hell what the rest of the world things, unless your weakenss is hurting somebody. Too often we are looking for approval. When you walk around or go somewhere and you tell yourself "This is who i am, and i like it", then your body will start showing it too, and after a while, it becomes second nature to you.
Most of us are afraid of failing and are too eager to please when we go for an interview and such things, or are too anxious to make a good impression, and this shows off in nervousness. Just try your best, TELL YOURSELF you've tried your best, and believe that when it doesn't really go your way, you've done your part.
Well, this are just some tips, i'll post some more if i can think of anything else. In all, confidence comes when you belive in yourself.
All the best to you
