Vacuum packing your belongings is a great way to store them for long periods or simply save space when traveling. That said, this usually requires that you go out and buy a special vacuum-sealed bag, but it turns out you can use the normal trash bags you have at home. Just take a vacuum and suck the air out of your trash bag while holding the opening around your vacuum's extension.
This should create the same effect as if you were to use some special, fancy bag. Just be careful not to let too much air back in when you remove your vacuum's extension.