Forget about intelligence

There's no such thing, really.
And if intelligence were anything but a construct, it still wouldn't be useful to think about intelligence in the context of doing well in exams.

The other night I had a parent say to me "My daughter wants to be a doctor but I keep telling her she's just not an academic student - her grades have never been that great."

Naturally, I was aghast.

So, what's going on here?

Well, a few things.
1) The immediate concern is that this parent's attitude and opinion may be negatively influencing their daughter's self-efficacy (belief in ability to achieve goals). It could well be that the parent wants to protect their child from the risks of disappointment. But that's just silly, because...
2) ...the more disappointing thing is if we don't strive for our goals. A healthier position, from my perspective, would have been to acknowledge that their daughter has set a challenging goal. From that position, the parent becomes a source of encouragement and support, rather than a source of oppression and limitation.
3) Past grades really don't matter. I was getting Ds in year 11. Now I am amongst the youngest Australians to have completed a PhD. All we need is a clear goal and the drive (and skills) to achieve it. Keep the focus on the future - find solutions to solve anticipated challenges, rather than sourcing reasons from the past to justify not trying.

It's not intelligence that distinguishes students. That's just a cop out. The real thing that distinguishes good students (and indeed, successful people) is determination.