First you accept yourself as you are. Accepting compliments, when someone tells you, that the dress you wearing, looks lovely on you, you accept the compliment. That must be a true compliment. If you are told that your cooking is great, and you know, for a fact, that it is not true, then the person is just trying to be polite.
To accept a compliment, you must be true to yourself. A person that accepts a compliment wholeheartedly, is a person that is not afraid to, take risks, is lucky, and, confident.
Try something embarrassing, like, karaoke, maybe, this will cheer you, and be confident. Do things, that you have been putting off for a while, you will, learn to accept you. Take a risk, it may not be as risky as scary as thought so.
If you believe, you are great everybody else, will think you are too. Challenge, any obstacle, this will make you feel good.