What is the best way to pack a suitcase?

Roll soft, casual items like t-shirts, jeans, and knits, which saves space and limits hard creases, and fold structured pieces like blazers and dress shirts, ideally laid flat on top or with tissue in the folds. Put the heaviest items, shoes and toiletry bags, near the wheels of a roller bag so the center of gravity stays low and the bag does not tip, and stuff socks and underwear inside shoes to use dead space. Keep liquids in a sealed bag, since pressure changes push them out of caps, and put anything you need immediately, medication, documents, a change of clothes, in your carry-on rather than a checked bag.

Packing cubes are worth it, but for organization rather than magic compression, they keep a bag from becoming a pile by day three and make security checks faster. The genuine space savings come from a decision, not a technique: pack a limited color palette so most pieces mix, choose one pair of versatile shoes plus whatever you are wearing, and plan to do laundry once mid-trip rather than carrying a fresh outfit for every day. Wear the bulkiest items, coat and boots, on the plane. Photograph the contents of a checked bag before you fly, which makes any claim far easier, and put a tag with your contact information inside the bag as well as outside, since external tags routinely tear off.