I used to be the type that never accepted a compliment. One because I never felt I was ever worthy of having one. I would always shut people down. Being told that I was beautiful or intelligent etc was a no go for me. I even recently shut down a compliment where someone said I was extremely nice. I laughed and said, "You do not know me. I am far from nice."
I shut them down hard and seeing that now I can see how I invalidated them as if they dont know what they are speaking, etc. It is a habit I am trying really hard to break. I need to just accept a compliment for what it is, even if I do not agree with it. Thee nicer thing to do is just to say thank you or smile and move on.
I have found this easier with my Masters in charge of me. They made it a rule of mine that I cannot talk bad about myself and if they give me a compliment I cannot deny what they are saying, and I have to accept it.
Their reasons behind it is because, do I believe they would ever decide to be with someone who wasnt beautiful, intelligent, or didnt offer anything? Of course they wouldnt. Plus they showed me that the way I feel when they belittle themselves is also how they feel when I do it.
So now I do my best to accept compliments. I am still a work in progress but it is coming about. I am learning, taking baby steps and adapting and growing as a person. I may fail to accept a compliment sometimes but I am aware that it happens and I make steps to move forward and striver to do better.