There are many different weaknesses that we experience. Some are psychological, some are physiological, and others are intellectual. Some can be overcome entirely, while others can only be partially overcome, or even require a work-around to deal with.
Some of the most common weaknesses stem from a simple lack of knowledge or education. A regular refrain in prepping circles is folks bemoaning their lack of skills! Luckily, these weaknesses are the most easily overcome: in our modern digital era, the barrier to education is incredibly low, making education and skill acquisition mostly a matter of desire and will. A simple Google search will provide answers to almost any question, and YouTube can show step-by-step instructions for a boundless number of tasks. Even vaunted MIT offers much of its coursework online for free.
These are a much larger obstacle to face. They may require help from professional individuals and possibly even medical treatment to overcome. For less severe cases, meditation and other mental exercises can be of assistance. In either case, the key is finding the root cause of these issues now and learning to address and overcome them now, during times of peace. That way, when an emergency happens and a psychological shortcoming could bite you, you've positioned yourself in the best way possible to deal with it.
While basic lack of strength and stamina can be corrected through exercise, sometimes injuries or genetic issues cannot be overcome ... at least not in the traditional sense. While I can always train skills or take steps to get my head right, there's precisely zero I can do about the fact that I'm 5'4". When you cannot simply correct the weakness, you must instead correct for it. Physical weaknesses are usually addressed in two ways: by altering the environment, or by altering behaviors.
Where possible, my house is configured in such a way that most things that I need aren't above about 7 feet from the floor. I've altered my environment to account for my height.
Sometimes weaknesses crop up that require changes in behavior patterns. My mom just got a pair of new knees, and part of her recovery has been altering how she does her job. She works remotely, which is a great help, but she can't sit and work for long periods like she normally could. Instead, she has to break up her day, making a point of getting up and walking around, in order to keep her joints loose.
One of humanity's greatest assets is the ability to learn, adapt, and overcome obstacles. Don't make excuses for weaknesses. Address them, attack them, and make them as minimal as possible. This is where you will find your greatest gains.