Pack Your Suitcase Perfectly By Seeing It Like a Game of Tetris or Jenga: some useful tips - it definitely helps to visualise the space in a bag, or the small nook left and think what can fit in, or what can be reoriented to give more room. I am not convinced though by the semi-rolling method used here
Packing cubes are a definite help when you have to use a large back and weight is less of an option - great for compartmentalising your things for easy retrieval. This set of 3 costs $30
How to fold a suit, pants and shirt to go in a suitcase without wrinkling: a different take to my now heavily preferred bundle wrapping technique but it looks good - the secret looks to be a cushion of air.
Like a camera, the best bag is the one you have with you. This folds up into my pocket but is pretty big and strong. This cost me only $30