Hi, Cadenza, I didn't mean to make anyone nervous with this thread, but realized after my first fail that I probably should have taken it a lot more seriously. I really and truly thought I was a good driver in the U.S. Having done well on the theory, and having taken driving lessons, I thought there would be no problem. I was wrong.
The things I realized late (that I know about so far -- I may pick up more here and on my next failed test, if I fail again) were that shifting with my left hand uses my right brain, rather than left brain as I used in the U.S. When I got nervous -- and one DOES get nervous on a 40-minute driving test -- I made numerous shifting mistakes -- not serious, but enough to rattle me even more. In correcting this in my practice after the first fail, I learned to force myself to transfer the shifting task from right brain to left every time, no matter what... every time I go for fifth gear I force myself to analyze the task and break it in parts, finding the junction in the gear box and pushing to the right.
As mentioned before, lots more mirror use is expected, including when you slow down or even speed up!!! And of course before signalling for and exiting a roundabout. They use the emergency break lots more here... everywhere there is the slightest slope for any length of a stop. (Expected length of stop and degree of slope combine in this equation... If you are stopping for a long time, use the parking brake even with no slope; If you are on a steep slope, use it even if you will be there the briefest of moments...) How good you are with the clutch covers some of the ground in between. The critical thing is NO ROLLING BACK (or forward).
Another thing that I learned early on from my instructor is that they really hate "coasting." This is moving in neutral or with the clutch in (e.g. coasting to a stop). I learned to drive a long time ago and consistently hit the clutch too early. You need to practically let the car sputter to a stop before hitting the clutch.
I think my main mistake was not getting an instructor that was just right for me. It would be good if you could find someone familiar with the problems of Americans learning UK driving... who understands that we are actually TAUGHT to steer hand over hand as the way to keep control of the wheel and have to work hard to unlearn that! Someone who understands that you might not have a clue what they mean when they say "nearside" lane.... And that the place you are most likely to go on to the wrong side of the road is turning right from the right (of two lanes) on a one way street onto a two-way street.
My instructor was great for beginning UK drivers, but just didn't have a clue what I didn't know but needed to know for the test, having driven so long in the US. You really should try to get some lessons with a teacher who really builds your confidence and is encouraging, but who also really "teaches to the test" very specifically and gets you driving not in what is just a safe way, but in a way that will pass the test.
Don't despair if you fail -- many many people fail here; it's just a different system than in the US. I suspect the roads are more dangerous, so they have to do what they can to increase safety by getting better drivers at the one control point they have -- new licensees. Just our luck that, unlike Canadian and EU immigrant counterparts, we can't exchange our licenses without going through the whole new driver testing system. At the moment this feels like bad luck, but in the long run, if we end up being better drivers, you have to acknowledge this is actually a good thing. Good luck to you any another others in the same boat (or car?) with us...