How can a person stop putting too much emphasis on physical beauty, especially when it's given so much priority in society? I want to stop getting so disheartened when I look into the mirror and start focusing on how God sees me. I want to stop judging myself and others beyond what is written in the Bible, but the difficulty is in escaping the way I've been thinking all my life. I have been insulted for practically all my life by friends and family about the way I look and that has left me feeling very insecure. And it's those type of insecurities that hold me back in doing the things I want to do.
That there is an overemphasis on the physical aspects of life is a given. That is why we find Peter advising women, "Do not let your adornment be merely outward--arranging the hair, wearing gold, or putting on fine apparel -- rather let it be the hidden person of the heart, with the incorruptible beauty of a gentle and quiet spirit, which is very precious in the sight of God" (I Peter 3:3-4). Not that this is limited to women, I've seen men just as caught up in the physical aspects of life.
But I don't want to leave the impression of complete unconcern regarding your looks. It is in comparison to spiritual attributes that it is insignificant. Yet, we are told to have some regard for how we look. "Let your garments always be white, and let your head lack no oil" (Ecclesiastes 9:8). Having clean clothes and making sure you smell good is important when you realize that you do have to deal with other people. If people are uncomfortable being around you because you stink, then it is going to be hard to hold a job or teach others about the gospel.
When someone uses a generalization, such as "everybody says ...", I usually wonder if it is truly everyone, or if it is possible that a point is being made that is being ignored. For example, if I repeatedly get told that I'm getting overweight, then eventually I'm going to have to face the fact that perhaps I should do something about the issue because it will eventually impact my health and my ability to work. Physical exercise has some benefits. "But reject profane and old wives' fables, and exercise yourself toward godliness. For bodily exercise profits a little, but godliness is profitable for all things, having promise of the life that now is and of that which is to come" (I Timothy 4:7-8). Without knowing what issues you are dealing with, I have to leave it with these general thoughts.
As far a you, personally, focus on seeing other people for their character and not their external qualities. How a person chooses to dress gives you hints about their character, but sometimes you don't know how much choice they have had about their current state. So always try to get to know people. Once you start seeing people as someone more than their surface looks, it will begin to rub off on you as well.