I managed to pass car and motorcycle tests first time. My dad's car was an automatic, so whilst I had had a fair bit of practice driving around, I had only done a limited amount of lessons in a manual car so reversing round corners and hill starts were a challenge. I remember on the test I got asked about sequence of actions before, say, a junction. As "changing down through the gears" had been drummed into me, I'd been changing down before signalling - this is a fault since you'll potentially have slowed down before the guy behind sees a signal or even brake lights. The examiner still passed me but explained the proper sequence - I've never forgotten. He was said to he a stickler, but I guess he let me off as I was presumably still signalling in good time and observing properly.
My bike test was a good few years later, so I had plenty of on road driving experience by then, and just had to master operating the bike, and the few motorcycle specifics. I knew I'd passed when the highway code question was something rather obscure about what to do if your luggage falls off whilst on the motorway, rather than what a stop sign means. My pal who started riding at around the same time failed by exceeding the speed limit which is pretty dozy. He was a sensible chap generally to be fair