When packing your clothes, you don’t want to neatly fold them individually as you would in a dresser. If you do, they will crease when compressed. Here are a couple of alternatives:

Rolling Your Clothes
Backpackers swear by this method. Rolling works well with pants, skirts and sports shirts. Lay the item face down, fold back the sleeves and then roll from the bottom up.

Fold Clothes Together
Take two or more garments, for example trousers, and lay half of one pair on top of the other. Fold the one on the bottom over the pair on the top. Then take the other and fold it on the top. This gives each pair some cushion where you’ve folded it so it’s less likely to crease or wrinkle in the folds.