hi,
well it's exactly the problem of many people.
these are the techniques which i applied myself:
stand before a full length mirror and speak in front of it or read aloud,
or U can imagine that there's another person in the mirror and U r talking to it.
at first U may feel awkward or hesitate, gradually U'll make it through.
and:
when U r alone, imagine talking to a native english speaker and try to speak english with her,or U may iamgine Ur familiar person and talk silently in Ur mind,
and:
read aloud, speak like americans as U say U r taking toefl classes,
concerntrate Urself in most of the sound which most of non-english speaker do mistake, specially south asian.
i'll be pleased to help U out,U can send me emails at yahoo/ hotmail at theeasternthunder
hope U'll find it helpful.
regards,
saw rose