Nephorm, if you’re out there; you’re one of the people I would really appreciate imput from.
First: everyone has areas they need or want improvement in.
There are many reasons you might have difficulty with certain subjects, particularly mathematics. One reason is that you might lack rigorous training in the concepts that precede what you are attempting to study.
Intelligent people often (sometimes implicitly or unconsciously) believe that they do not have to do the “grunt work” of learning; years of doing well without effort have a way of making one lazy when confronted with challenges. It is also easy to underestimate the impact of missing bits and pieces, here and there. For example, maintaining a B- average in math for 12 years (an 80% average, let’s say) means that you are missing “20%” of the material. Obviously there are all sorts of reasons for that B average, but you get my point… missing out on basic concepts can cumulatively harm you, especially as you attempt to learn more difficult concepts that draw on larger portions of what you are supposed to know.
Another reason might be that you aren’t being given what you need in terms of explanations.
Many textbooks are not designed to stand alone; if your teacher’s explanations and elaborations are not helpful, or if you are used to tuning out teachers as a matter of habit (see my “grunt work” comment above), it might be difficult to pick up the slack of the text.
You have options. You can play to your strengths and slack through your weaknesses, or you can bust your ass and do what it takes to increase your competence. No matter what, there probably will not be a quick fix that solves everything.
Wikipedia and other online references are your friends. So are office hours for TAs and professors. The trick is to have real questions to ask before going in. Don’t ask questions you can answer with a quick search on google.
Ask questions based on how the concepts interrelate. Many campuses have tutoring services… there’s no shame in utilizing them, as long as you don’t treat them as a crutch.
Learn to ask the questions “why?” and “what does that mean?”
I do not know whether you will be one of those infamous high-IQ types who “don’t do much” with their lives. Only you can answer that question, and only then by honestly assessing (if you can) what it means to “do much” with your life.
Many smart people will opt for a reasonably enjoyable job that provides enough money to afford to do the things they enjoy and support a family. Different goals require differing levels of dedication to different areas of one’s life and education. You have to decide how hard you are willing to work.
I’m confident you can do, and learn, what you set your mind to doing and learning.