This should seem obvious to most but I started to realize it's not, especially in the younger performers of today.
Learn proper self-deprecating humor.
No one seems to have ever given the advice that self-deprecation should apply to your personal faults NOT how much you suck at something. If you think self-deprecating humor involves making fun of how un-skilled or your lack of talent is, then you need to STOP. You diminish not only your work but the work of others who actually try to be good.
However, if you wear glasses and are blind, harp on that. Does your fashion sense denote your mother dressed you for school? Go to town on it. Are you bad at math? Make that funny. This is proper self-deprecation. Not that you suck at magic, or juggling, or whatever.
People want to see someone be proficient at their craft. If you are using the "I suck at this" gambit as a premise so when you do something really skilled it surprises people that's different but find more subtle ways to get that across than outright saying it. (However going that route takes more skill in some ways than learning sleights so tread carefully)
So even if you do suck and the whole world knows it don't point it out. You'd be surprised who you can fool.
Never let em' see you sweat.