It's a hard-to-swallow, uncomfortable truth, that you can be a barrier to your own success. I think it's worth caring, or at least asking, about why this is, and where it applies.
There's a clear difference between healthy self-criticism and defeatism. Developing a fairer, more open-minded idea of yourself is important in lots of ways. But particularly in career terms, it would reframe what you might see as impossible dreams, into genuine opportunities or challenges. It may be hard to perceive, but you are more than your current skill set; your potential, your growth trajectory, your capacity to learn and adapt are as valuable as the aspects that presently define you. There are many ways in which we underestimate, and undervalue ourselves. Your self image deserves to be expanded.
I think Antonio Lucio is half right when he says that self-advocacy is 'the ability to say what you need, want and hope for in life'*. But what he misses is that most of the work comes in figuring out what we actually want, admitting it to ourselves, and voicing it to the right people, when it matters. We witness good self advocacy in people who ask for promotions or raises, for instance. Or in those who will claim credit when and where it is owed to them. Or, even, in those who see an internship/job listing they like but aren't a perfect fit for, and still go ahead and apply. In many cases, no applicant will be a 100% match with the 'desired profile'. That's why it's worth giving the application a shot, and, while recognising your shortcomings, showing how these can be improved or compensated for through your other skills/qualities. Every single one of us is a work in progress, there aren't any finished products out there: an attitude like that one, then, will go a long way.
The truth is, many of us fall into that catch-all category of 'insecure overachievers'**. We experience a mismatch between the person we are asked to display, and the person we think we are. But the onus on each of us to move past our spikes in self doubt, becomes key. The ever-changing way in which we see or feel about ourselves should remain divorced from the way we project ourselves professionally. Establishing that separation is both healthy and important in the competitive world of application-writing. Whether through CVs, cover letters or interviews, the well packaged exterior that you present should not reduce or define you, nor act as a judgement of your personal value. At the end of the day, your professional persona is just that - a mere persona, tool, or display, rather than an indicator of self worth. That's a huge part of what it means to be a better self advocate; your innate value does not, and should not, enter the picture.
These are psychological traps that affect us all, and that is precisely why they matter. In moments where self advocacy is needed, be it out of hope, ambition, or frustration, it might be helpful to imagine yourself, and your context-specific persona, as being in 2 distinct spheres. However bruised the latter might be, the former should remain intact.