How can I learn to accept compliments more graciously?

Two nights ago I went to Dunkin Donuts with a friend. She knows I don’t drink coffee but, after placing her order, she jokingly said to the cashier “she would like one, too.” I started laughing and told him that she was just kidding. He then said to me “you have such beautiful complexion.” I (awkwardly) said “thank you” and he proceeded to tell me how beautiful I was. I waved him off dismissively and jokingly said to my friend “he’s just saying that so I can buy something.” Later she retold the story to one of our guy friends and he told me that I need to learn to accept compliments.

Then yesterday, while at work, the same friend with whom I had gone to DD the night before was having a conversation with the guest she was assisting (they happened to be from the same town). A friend of the guest’s, who had been waiting for her in the lobby, came up to the desk and joined in on the conversation. He pulled out his camera and took a picture of me without my noticing it. My friend told me to wave to the camera and I asked why, to which the guy replied “you’re really cute.” Although I was appreciative of his compliment, I (again) waved him off and walked away.

I’m not a rude person by any means but I’ve been thinking about my reaction to these two situations and I’ve come to realize how ungracious and snobby I must’ve come off. The worst part is that this is how I always react to compliments. My managers and co-workers constantly compliment me on my wok and yet I always dismiss them and whenever someone compliments me on my looks, I blush like a lunatic and wave them off.

I don’t have low self-esteem and am happy with how I look, so I don’t really understand why I react the way I do when given a compliment. My only guess is that it may have something to do with the fact that I hate being the center of attention. Growing up, my parents always impressed upon me the importance of being humble. However, I fear that my modesty makes me come off as ungrateful and rude.

How can I learn to accept compliments more graciously and not offend people with my unintentionally rude reactions?