La théorie
http://www.elementalenglish.com/how-to-understand-native-english-speakers/
Les techniques
PRACTICE
Listen and answer questions
http://www.tolearnenglish.com/free/audio/indexg.php
Listen and find out the hidden words
http://myweb.tiscali.co.uk/wordscape/listening/hidden.htm
More of the same :
http://myweb.tiscali.co.uk/wordscape/listening/