In order to be humble within, which you would need to be so as to be humble in your deeds, you would need to realize a number of important things. First and foremost, the fact that no one truly deserves to “be praised by others, honored by them, and all the more so, to be held above others by them” (in Ramchal’s words) as we’d often like to think of ourselves.
And that is true for a couple of reasons: first, because no one is without his or her faults, no one. If Moses, our master, was faulted by G-d Himself for his anger and impatience, then who among us could claim to be above him and faultless? And second, because each one of us has sinned or lapsed into one ethical or ritual trough or another, and thus no one can claim to be above others in any of that.
For irrespective of one’s good points, his lofty perch on one level or another, his achievements, his earned praise for one thing or another, each one of us has our defects and blemishes despite it all.
And while a person’s faults may be “a result of his nature, of family influence, or of circumstances” which are all beyond our control and which we tend to accept more readily in ourselves; or “they may be a result of certain of one’s own actions” which we’re all forced to acknowledge, it hardly matters. For the truth of the matter is that “No man is so righteous that he would (only) do good and never sin” (Ecclesiastes 7:20).
“All of these are … personal blemishes that could never allow for self-aggrandizement,” Ramchal surmises. In truth, he concludes, “even if you were an otherwise extraordinary person, your imperfections would be enough to overshadow your other traits” and you dare not consider yourself praiseworthy.
At bottom it comes to this, apparently: while we’re each to be acknowledged for having grown in one sphere or another; for having rounded-off one or two edges by dint of hard work and good intentions; and for taming the little boy and girl in our selfish, selfish hearts to a degree, the lot of us are imperfect. And none of us can afford to be so nervy as to place him- or herself above anyone else overall.