Confident men don't get dragged down by pettiness and insecurity. They surround themselves with the opposite. They find supportive people and make an effort to stay in and touch and keep these special individuals as a part of their lives.
To feel more confident everyday, don't let people who don't support who you are and what you want into your life. These people are often hard to identify at first; their words can be sly. But you'll learn who drains your energy and who uplifts you. Confident men only keep company of those who support them. So just let go of any relationship (work, friendship, intimate) that will drag you down.