Can you build up your self-confidence? YES!
How?
- stop being your own worst critic, and stop degrading yourself.
- be realistic about expectations; your own and others. Are they realistic?
- understand, acknowledge and accept that NOBODY has only weaknesses, as well as nobody has only strong points.
There definitely are things you can do or know better than others! So what, if there are some, that can do some things even better, or have more knowledge in any given field than you. That does not make you a lesser man. There will be other things in which you are better than they.
What's the difference in those people with more self confidence? They don't care, if someone is better at something than they are, they know they are good enough for their purposes. Or, if not, that they can improve.
And as to writing - you can study and learn languages, grammar, style, to research thoroughly - but none of this gives you ideas, emotions, phantasy. This comes from within you, from what and how you are as a whole human being.
From what I have read of you, you are much, much better than what you say here what you think you are!
But maybe your problem is not self confidence at all? If it is a question of not being sure where you (!) want to go, to be able to define your (!) goals in life, and where to find the tenacity in pursuing them? That I would consider another issue, not suitable for public discussion (for me at least)
