The quickest dirty hack is using Anki or another spaced repitition sytem program. If you download Anki you can get at the shared decks and there rea some very nice ones for German vocabulary.

For speaking/understanding speech I've heard great things about Pimsleur. Once you have the rudiments of the language listen to podcasts all the time.

Learn the grammar. You are unlikely to pick up more than the utter basics by osmosis. Good luck!