The Lifehacker site has many useful travel tips. Many of us need to travel on client business, which means packing a suit. Carrying a heavy garment bag is not fun (indeed, air travel in general is not fun). So it is important to find a way to fold a suit jacket so it will fit in a small carry-on bag or even a backpack without getting wrinkled. Here's how.
1. Hold the jacket facing away from you. Then turn one half of the jacket, sleeve and all, inside out.
2. Slide the right side sleeve inside the other sleeve and gently pull it all the way through.
3. Fold the two sleeves across the rest of the jacket and put a rolled up t-shirt under the shoulder pads so that they hold their shape.
4. With the jacket laying flat, straighten the lapels and collar to align.
5. Start at the top of the jacket and roll downwards.
If you also have pants that go with the jacket, fold them in half lengthwise and roll around the jacket bundle. Now you have a compact roll that will fit easily into your carry-on bag! Travel+Leisure has a full step-by-step with pictures at the link below, so check it out if you want to see the method in action.