Spanish with Michel Thomas worked for me. It teaches you the structure and rules of the language - no books or need to write anything down.

Also, when you have a basic grasp, buy the Spanish language version of a book you have read in English. This helps as you already know the story so you can make sense of the bits you don't understand.

The first one I read was 'Sobre Limones' - 'Driving over lemons'  by Chris Stewart

A bit later I read 'Brujas de viaje' (Witches abroad) by Terry Pratchett, thinking it would be easy to read - now I have Spanish vocabulary for werewolves, goblins, fairy godmothers etc. which proves very useful in day to day life  ;D