The tangerine technique is most useful for regular reading, it doesn't seem all that magical.
While you're reading this, actually cup your hand as if you are holding something that would weigh about the same as a tangerine. You know that the tangerine is a bright orange. Can you remember what the texture of the skin felt like? Let your memory bring that back to you what other fruits have a similar texture? You can toss this imaginary tangerine from hand to hand, remembering what it would roughly weigh. Once you have it back in your dominant hand bring that hand to the top back part of your head and actually touch that part of your head, bring the hand down while noticing the sensation on your head.
>>"i feel stupid doing it"
Actually you might feel a bit self conscious because no one else does this, once you have actually done it you can just touch the back of your head to trigger the effect an later just remembering what it felt like is all you need.
Once you feel okay about doing the tangerine effect you will notice the wider view, better concentration and it will seem easier. The tangerine effect isn't the photofocus of photoreading... it is for effective regular reading. So it is regular looking that allows your eyes to notice groups of words rather than just one word at a time.
If you haven't read the whole book yet, consider reading it as outlined in the front page before actually going into the exercises. Having that overview helps make all the techniques fall into place.
Alex