You can't be great at everything.
In fact, if you want to be exceptional at anything, you're going to have to reside in the fact that you're probably not going to not be great at a significant number of other skills.
This is because it takes a lot of practice to become great at something and for most people there's just not enough time in a lifetime.
So it helps if you decide on the things that you are or want to become great at. And become comfortable with just being ok with the rest. You can partner with or employ people who are great at the things you are not.
“Success is no accident. It is hard work, perseverance, learning, studying, sacrifice and most of all, love of what you are doing or learning to do.” — Pele
When you feel like you should be amazing at everything, you compare your weaknesses to other people strengths. You try to do everything, instead of just focusing on the things that you are good at, and letting others fill your gaps. You butt heads instead of collaborating.
I am guilty of this sometimes. And I know how much it helps to be reminded of what I'm good at, and what I'm not.
The best tool that I have found so far for accurately assessing and describing an individuals top strengths is the Clifton Strengths Quest.
Once you've figured them out, put them somewhere so you're reminded. It's easy to forget and slip back into old thought patterns.