I’m short. Really short. I’m only five feet tall. In a fight, I have no reach advantage what so ever. That is something that I can not change. As a fighter, that is my greatest weakness. One of my strengths is speed. My karate instructor taught me to use my speed to over come my lack of reach. First, he trained me to cover large distances quickly. Next, he taught me to time my advances. Then he taught me to distort the visual perception of distance and speed. (See also How Fast is Fast.) Now, when my opponent looks at me, they assume that they have the advantage of reach. They are lulled into a false sense of superiority. Then we start fighting and before they know it, I have advanced inside their reach and eliminated their advantage. The result is that my greatest weakness became my greatest strength.
People in BJJ have been doing this weakness / strength reversal from the beginning. They compensate for physical weakness, by developing extraordinary technique. They literally use their brain to overcome brawn.
What are your weaknesses as fighter and how have you overcome them?