1. Wash and dry your hands
Wash and dry your hands before practising with your cards. Washing your hands will prevent any rubbish or food on your hands to be transferred onto your cards and make them sticky. Sticky cards are not great for card manipulation which require the cards to slide e.g. card fans.
Also ensure your hands are dry. If they are wet, the cards will absorb the moisture and you will see moisture marks on your cards. And also make them stick together.
2. Use 1 card to scoop
If your cards fall on the ground (and they will), use 1 card to scoop up all the others. This way, only 1 card will be exposed to the dirt and dust. Blow and wipe any excess dirt off the others cards.
3. leave them in the box
Keep the cards in their box and in a cool place. This will ensure no cards are lost and that the cards will straighten. I have found that even my own body heat can warm-up the cards and the cards will bend. For example, if you keep the cards inside your jacket pocket near your chest, the heat from your chest will cause the cards to mold into the shape of your chest. Keeping your cards in your pocket (close to your crutch) is definitely NOT a great idea.
4. Practise with cheap decks
Practise with cheap decks. I always keep a couple of cheaper decks handy and rotate from deck to deck.
5. Rotate decks
I have found that rotating from deck to deck is just as effective as putting a deck of cards in the freezer or using fanning powder. And less of a hassle. Putting a deck cards in the freezer can expose it to moisture. Fanning powder requires a bag and an open space. I was never able to open the bag and extract the cards without breathing in some fanning powered. It can’t be good to breath that stuff in. But that has been my experience.