You're right, you can fail for "little" things, however those "little" things are usually critical and related to infection control (basic precautions like forgetting to wash hands, change gloves when required or picking something up off the floor), safety (not locking wheels on the bed or wheelchair will fail you), privacy and dignity (not pulling the curtain closed or knocking and doing the introduction/explanation bit) and even not zeroing out the scale when you weigh an ambulatory patient. All "little" things but all critical.
I think the best approach, when you find out which skills you get, is to consider the final outcome. Is the patient safe, protected from unnecessary exposure to pathogens, comfortable, and do they have a call light available if they need something? It's so easy to get caught up in the steps it's hard to step back and think about what you're really being tested on, which is ultimately your sensibilities in a real life situation. Be in control. If you forget something, make sure you tell the evaluator you forgot but you would do whatever it was, and actually do it if time permits. They appreciate your nervousness and stress level, but can't give you credit for any skill if you overlook the basics.
To answer your question: Lots of people fail the first time. I took my skills test with a woman who failed THREE times and had to go back and take the course over again. Her problem was dyslexia and she recorded numbers backwards. She finally passed on her fourth try (I saw her name on the state registry). Her perseverance was impressive, to say the least.
Practice the skills that confound you. Remember the basics. Know the skill but don't get too wrapped up in the sequence of steps.