What are your goals and interests?

Here is some generic advice around getting to the mindset that lets you freely grow your intellect and personality:

One area I would start in is removing the link between your self worth and whether you are considered "smart" or "stupid". You must realize how unreasonable it is to presume that you are incapable of something (though it may take some effort). People of fairly average intelligence have achieved far more than many "geniuses" throughout history.

Labels, even positive ones, are inherently limiting. I have seen some of the smartest and most talented people I know be completely crippled by their fear of being seen as "stupid" or "untalented" because they place so much value and self worth in being viewed as smart and talented. Once you start labeling yourself as atheist, smart, Christian, lazy, stupid, disorganized, unkempt, useless, handsome, ugly, etc. then your natural tendency is to both do things and believe things that validate those labels. They become a crutch, a shelter, and they let you stagnate.

Don't compare yourself to other people. It is of little value, even as a benchmark of where you stand in the general population (because it is both extremely difficult to get a representative distribution and because biases in how the brain processes information will tend to confirm whatever your current beliefs are, among other things). You are where you are, and having a good understanding of that lets you plan and grow accordingly.

Cultivate your interests and curiosity. Being genuinely curious about things will take you further than you think is possible. Don't ever let yourself be bored. Try not to have self limiting thoughts. Always look for ways to improve. Limit how much time you spend consuming non-technical/simple things (television, reddit, Facebook, video games) Take care of your health. Focus on making important things lifestyle changes (that is, create lasting support structures for what you should be doing, and things that make it difficult to do the things you shouldn't do).