1. Listen through the dictation the first time and transcribe everything you can easily hear. Leave blanks for anything you aren't sure of. (Feel free to leave yourself "sounds like" clues in your blanks.)
2. Read through what you transcribed WITHOUT THE VOICE FILE. Correct any obvious grammar and/or spelling errors. Read the report like you would a story - connecting the dots in your mind and making sense of what you are reading. You may be able to fill in some blanks this way.
3. Go back over the dictation a third time - this time listening to the voice file and stopping on your blanks. Don't spend more than 5 minutes per blank. If you're struggling to make out a word, try writing it down phonetically. Then try pronouncing it out loud by putting the emphasis on different syllabus. For example, you hear what sounds like "eye-bip-row-fin." Say it the first time out loud emphasizing the first syllable: EYE-bip-row-fin. Then: eye-BIP-row-fin. Then: eye-bip-ROW-fin, etc. Then try running some of the syllables together: eye-biprow-fin. Or eyebip-rowfin. In the case of this example, hopefully you will eventually hear "ibuprofen."
4. Go over the transcription one last time without the voice file - again reading out loud and trying to understand the story being told.
5. If you end up having to submit the report with blanks, it is imperative that you go back over the report when your instructor or QA person completes it. If you have the opportunity to listen again to the voice file, I highly recommend it. This way you start to make the connection between what you are hearing and what belongs in those elusive blanks.
The truth is, you can master anything that you spend valuable time practicing. The only way to master the language of medicine is by repeatedly being exposed to it. Watch medical shows on TV, listen to medical podcasts online, and concentrate when you sit down to the keyboard to do your work - whether for an instructor or your employer. At the end of the day, always aim to do your best. Treat every medical record you work on as if it was your own.