The core is issue is a faulty belief that you are flawed in some way.
It is easy to rationalize why we may be flawed or inadequate, but it doesn't make it true.
It is my belief that you are perfect exactly as you. Every bit of you, especially the flaws... perhaps we just have the wrong perspective on them at the moment.
I would suggest making a list of all the reasons WHY you feel inadequate: every failure, weakness, shortcoming, etc. After you have that list, ask yourself the question for each item: "How does this serve me? Where is the hidden gift that I'm overlooking?"
Critical in this process is letting go of the inclination to compare yourself to others. Inadequacy can thrive when we think we are "less than" others, or what we "should" be. However, we need to appreciate that we can't see everything about other people, usually only the things we feel we are lacking.
Respect the individuality of yourself, and others, by acknowledging that each of us have own own unique life path, and will learn and develop in ways that are needed exactly for us, at exactly the right time.
I'd recommend Loving What Is by Byron Katie. That is an amazing book on this topic, and will be a great help. :)