I am currently perfecting and practising front and back palming of cards (the lesson in Tarbell 2 concerning card manipulation).
I learnt it years ago and want to practise it more and get it very slick (watching that Cardini vid on youtube made me realise how I need to work on it more!)
I find when moving the card from front to rear it makes a sound and no matter how many movements I have tried to change it still does it. This kind of sleight needs to be performed quickily so the specs eyes don't catch a glimpse of it, I just don't want their ears to either!
If you are planning on close-up, usually you are in a setting with other people around. Most of the time there will be enough background noise to cover the sound of the sleight. Or you could invent a little patter for that exact moment to cover the sound as well.