Re: mental horsepower, I think someone can’t actually raise their IQ from e.g. 120 to 150, but a 120 that has learned a lot of tricks can often operate at a similar level as a 150 who hasn’t.
- Learn about creativity techniques with https://www.amazon.com/dp/B004CFAWU2/
- Learn about negotiation techniques with https://www.amazon.com/Getting-Past-Negotiating-Difficult-Situations-ebook/dp/B000PDZFDO and https://www.amazon.com/Getting-Yes-Negotiating-Agreement-Without-ebook/dp/B0051SDM5Q
- Learn about management with https://www.amazon.com/High-Output-Management-Andrew-Grove-ebook/dp/B015VACHOK
And so on.
Re: weak vs. strong — I think it’s both. If you have some weak traits, you can get around them if you assemble a complementary team, but otherwise they often lead to failure. OTOH, having one or two killer strengths can be a huge advantage — but only if they’re not paired with killer weaknesses =).