As good as the above advice is, my advice to you is be confident. When kilted be conscious of your posture, stand tall and proud. It takes a special man to don the kilt and that will show through. I offer this photo for you to judge whether or not it looks like a fat guy in a skirt or a is it a man who knows how good he looks. (I don't mean to be stroking my own ego, it's just that I like this pic.)