Establish the key signature. With the song playing in the background, run through the major scales on your instrument. Until you find the right scale, your playing will clash with the music in the background. For example, if the song is in the key of B major and you are playing a C major scale, almost all of the notes will clash. Once you hit the right scale, you'll hear harmony between what you are playing and what you are listening to. Write the key signature down on a piece of staff notation. Key signatures are denoted by the flat or sharp notes in a key. For example, G major has one sharp note, F sharp. Put a sharp symbol on the top line of the staff to show that F is sharp.
Establish the time signature. Tap your pen along to the beat of the music and count each accented note. The accented note typically represents the start of the measure. Figure out how many beats are in the measure by counting until the phrase is repeated. Write the time signature down on a piece of blank staff notation paper.
Break the top-line melody up into measures. The top line is typically the lead vocal. Listen to four measures of vocal, and then play it on your chosen instrument. Once you think you have it, play along with the song. Any wrong notes you have will clash. Correct the wrong notes, and transcribe what you played onto the blank staff notation. It may seem daunting to transcribe a whole song, but it's likely that many parts are repeated.
Make a note of the sonic characteristics of the sounds. When you hear something that you find hard to transcribe using staff notation, make a note on the manuscript. Make your note directly underneath the measure or beat that the sound happens in. Write down the register of the sound -- for example, "high," "low" or "sub-bass." Draw a horizontal line under the notation between the start and end point of the sound. If the pitch ascends, draw an ascending line. If it goes up and down, draw a zigzag. This is called graphic notation. Assign a simple name to the sound, such as, for example, "high-pitched scrape" or "rumbling crash." Use these descriptions if the sound is repeated rather than writing out all of the notes again.