Not on what you never will be...
It is a process of self discovery.
The best thing we can do for our own development is to know ourselves well enough to realize where our strengths and weaknesses are. Doing that will lead us to is figuring out how to maximize our strengths and just as importantly figure out what our weaknesses are and determine which we can progress in and those that we cannot. There are some things we are never meant to be or have the skill to advance. Additionally we have some talents we are good at and should take the time to hone and develop to discover how far to take them. Attempting to foster what we have a knack for very often leads us to discover that is not our forte but along the way we uncover where our true abilities lie.
For instance I once was a mediocre singer. I developed the talent as much as I could, well enough to sing in public at gatherings and events. The result was I recognized that my vocal ability was limited to a certain range, type of music and that I could only advance so far. Eventually I gave it up not only for the reason that I was putting energy into something I wasn't all that great at doing but through the experience I realized I was good at public speaking. The conclusion is I determined where my real skill was and then maximized it. Another thing I learned from music is I grew up playing the piano and guitar but recognized I wasn't very good at either one and focused on writing lyrics instead. Taking from that experience I developed my other writing skills.
Through self discovery you won't spend time and energy trying to be something you are not and will never be. You then are able to direct your efforts figuring out what you do best and can improve upon. It is alright to try evolving certain abilities you may do somewhat well at to discover your limitations with them since through the experience you will likely discover a true aptitude worth improving. Decipher what you will never be very good at or don't want to improve upon. Then direct your focus on cultivating what you are already good at or have the capacity to develop no matter what it is. This can be artistic, academic, working with tools, people or any myriad of gifts worthy of being honed. It also doesn't mean if you'll never be a great painter that you shouldn't pursue it for your own pleasure, simply recognize that it is not one of your best skills and through it you may learn you are a great photographer.