Do not fold, and keep clothes inside out
If you are an experienced traveler, you know that there are trips, which last as long as a month, yet you must stuff all your clothes and valuables into a pack that is the size of a wine box package. Hikers and backpackers know this very well, and they all agree that rolling is superior method of stuffing clothes as compared to folding, because clothes rolled tightly tend to occupy less space than folded clothes, and they force you to utilize the entire space in the bag. The other advantage is that there are less chances of folds forming wrinkles. One of the most important hacks: you can easily save space when packing your bras and inner wear by stacking them on top of each other.
A useful tip for light colored clothes: to stop creases before they form, arrange your whites and pastels inside out to protect them from dirt that may enter your bag.