according to david oates (who though i don't agree with his methods and motives has studied the phenomenon thoroughly and has a bit of an understanding of the whole thing), a reversal in common conversational speech occurs every five to ten seconds and a quite less often in rehearsed speech and more often in the midst of heightened honesty and emotion. the technicalities of finding reverse speech are simple: get some audio recording of speech, be it a tape, a wav file, or whatever, figure out some way to play it backwards, and since the sounds and patterns are a bit different from forward speech it may like another language seem to go by too fast to pick up, so it may help to play back at lower speeds, listen to the recording a few seconds at a time in reverse at normal and lower speeds over and over until something becomes clear. of course, take great care to not let what you want to hear get in the way of what you actually hear, or your reversals will be nothing more than an audio inkblot test on your part. listen to each section objectively until words become clear, and when you think you've found something, play that section forward to see if it's a logical idea to be occuring in the subconcious mind of the speaker according to what is being said forward.
i have found that the absolute best way to listen to reversals is with a sound card and some waveform-editing software, such as sound recorder which comes with most versions of window(a very good program for this purpose, with no distortion and easy speed changes), syntrillium's cool edit, which allows you to change the speed of a sound without altering the pitch with only minimal distortion, or some similar program. it helps to use head phones or at least turn the soundcard speakers way up to hear the sound with the best detail possible.
on the content level, reversals may have a singsong, choppy sound and the phrasing may be a bit dreamlike and not completely logical, and they often make reference to archetypes of the jungian collective unconcious. for these reasons, i like to copy the speech style of reversals in lyrics and poetry to give it a deeper psychological effect. all the tools and resources you need to interpret these deeper meanings are already inside your head as long as you are a human being, but if something seems archetypal and you aren't sure exactly of the meaning, look up the things it makes reference to in books or on the internet somewhere. common examples of these are the soul, the wolf, satan, adam, eve, the snake, the owl, various herbs, the four elements, and characters from mythology and legend. also, there are those people like t.s. eliot who make up their own symbols which may be a bit more difficult to interpret. keep in mind that everyone's reverse speech is a deep window into their souls, and in hearing it you will find truths as harsh as nature.
(c)1999 flaming jo productions