Here are some guidelines to demonstrate how we currently view grading.
There are several things we consider when it comes to grading an app. First of all will skills are generally determined by looking at the characters personality. If there are detailed explanations of their mental prowess, their forceful will, or their acute focus written out in the will skills, the character will have a much better chance of attaining reasonably high skills. That isn't to say that the personality is the only area these skills can be drawn from though. These can also be influenced by looking through the history if there are notable examples of it. As an example, if the character's personality would merit and adept or advanced willpower, but they have multiple convincing displays of this skill in their history, it's possible that the skill could be bumped up to advanced or elite respectively. The abilities of the character may also be relevant if they indicate a high level of understanding or usage of the skill.
When determining tier, we look at the level of power the character displays in their history. As an example, because that will be the easiest way to describe this, if you were to write in your history that your character trained for a year, but were very vague on what this training entailed, then there wouldn't be much of an argument to be made to give them a medium to high tier. If, on the other hand, you were to write out that your character trained for ten years under a prestigious (X) master, went into great detail as to what exactly this training was, provided clear and consistent challenges for the character, and portrayed them to be of a high level, you would have a strong case to make.
As for abilities, we take a common sense approach to them. If your abilities are overly one sided, in the sense that the opponent has very little to no recourse, they will almost certainly not be approved. A possible exception to this is if the ability has severe, clear, and fair downsides. Another thing we consider is how much of a boost a character gains from an ability, and how long that boost lasts. You can, in fact, include some pretty hefty boosts, as long as they are limited to a reasonable amount of time, and the drawbacks are severe enough. Say I wanted to give my character a five times boost to their strength. If I were to say it was an ability they could activate at any time, with no drawbacks, no post limit, and no real ability to counter, it would certainly be denied. If I said instead that they would have this boost but that it would be a massive drain on their energy and they would almost be out of the fight afterwards, their durability was lowered as well, and that they could only maintain it for a few posts before it went on cool-down, that would be much more acceptable.