What are you good at? Do you even know? Have you seriously thought about it, or have you been so busy thinking about what you're not good at that you have not even noticed your abilities?
The Bible says in Genesis 1:31:
"And God saw everything that He had made, and behold, it was very good (suitable, pleasant) and He approved it completely."
In order for you to enjoy life, you need to know where your strengths lie. Thinking about what you are good at is not conceit, it is merely preparation to do your job with confidence. I know that anything I am good at is a result of God's gifts, talents and abilities in me, and I thank Him all the time for these blessings. Make a list of what you are good at and rehearse it daily until you gain confidence in your abilities.
I also realize that God brings people into my life who are strong in the areas where I'm weak - this keeps me humble and reminds me that it is not all about me.
"Your hands made me and formed me; give me understanding to learn your commands."
God created you to be great and you can trust His design!