Some advice that helps me through the process:
Whether you make it to the final round before you are cut, or don't make it past the first, that doesn't mean you aren't good enough. There are tens of thousands of applicants every year — and the number seems to grow each year — and only a few dozen spots to fill. There will be a prodigious attrition rate. Chances are, the deciding factor has nothing to do with your grammar, formatting, nomenclature, or spelling. While these are all very important and you want to do your best to have those basics down, there have been applicants cut that have had perfect everything. As Syndrome said (paraphrased), "When everyone's super, then no one is."
The committee has a set number of applicants they will choose to move onto the next round, and each subsequent round until they get their panel. These quotas have already been decided and none of us will ever know the exact stats. They will choose the applicants each round that they believe will make the panel. They love to make their jobs nearly impossible for the final round, when they have to make the final cuts, because that means they really have the best of the best in front of them. But that doesn't mean that if you're cut you aren't among the best. Not everyone can make it, there simply aren't enough spots. Keep trying. Rumor has it the committee likes persistence as a bit of a tie-breaker. There've been several panelists that applied for 4, 7, even 10 years before they were finally selected. So don't give up as long as you are eligible and interested. Like me, you might not make it year after year, but you definitely won't be selected if you don't even apply.
So keep your heads up, try not to stress about the process. Answer the questions to the best of your ability, and let fate take over. As Walt said, "Why worry? When you've done the very best you can, worrying wont make it any better." And if you make a mistake, try not to dwell on it. Sure, that typo might have been the reason you didn't make it to the next round, but it's not like you can go back and fix it, all you can do is learn from it and try to avoid making the same mistake next year.
Good luck to everyone! Hakuna Matata!