Figuring out why you lack confidence can help you target those feelings.  Start writing a "self-esteem" journal, where you note when you feel more and less confident about the way you look. After a week or two, look back at your notes and try to find patterns to the way you feel.  Were you more confident in any of the following situations: after spending more time grooming or getting ready, if you dressed a certain way, spending time in smaller groups, spending time away from certain individuals, or spending less time on social media or looking at celebrity media?  Are there any "bigger" issues, such as your employment status or personal troubles that seem to trigger your feelings of low confidence? Some people turn this type of anxiety towards their self-perception, which may seem easier to deal with than the “bigger” problem of job security or personal problems.  If you don't see any patterns or you're still not sure what is causing your lack of confidence, you may want to try a number of different tips to find what seems to help the most. Dr. Vivian Diller has a number of different cognitive-behavioral techniques for improving your confidence in your looks, which she calls “beauty self-esteem.” These techniques focus on evaluating the source of your self-esteem, questioning your negative opinion of your looks, and thinking about ways to think about your looks more positively. Focus on sitting up straight with your chest pushed out while doing the following steps for maximum confidence. Write the 3 things about your looks and the 3 things about your personality that you like the most. Place all 6 items in order of importance and write 1 sentence about each. For example, “I help others. I volunteer every week for a local charity and always call my friends back right away when they need to talk.” Notice where the physical features ranked relative to your personality features; most people rank personality features above physical features, which emphasizes not only that our self-esteem is influenced more about...

TL;DR in Chinese:
判断自卑的来源。 端正你对自我形象的看法。 写下你的积极特质。 分析你的积极特质。 你最满意的3条外貌特质，每条写一句话描述。 照镜子。 持怀疑的眼光看娱乐媒体。 把消极情绪转化为积极情绪。 写“自信日记”。 咨询心理医生。