Well, for one, the classical intelligence tests mean nothing. They only test certain fields on "intelligence" and their original purpose was to come up with a good age for kids to start going to school.
For example, they don't measure many of the intelligences in Gardner's theory of multiple intelligences. Actually, most of them are impossible to measure. How can you measure bodily-kinesthetic intelligence, for example? Or musical intelligence?
In my opinion, those who do well in intelligence tests are the kind of people who know how to do a test. In my case, my performance goes down especially when I'm under a strict deadline, such as in tests. I end up focusing more on time efficiency than accuracy of the answers. Well, this is the case in subjects that I don't do so well in, such as mathematics and physics. In the subjects that I do well in, that is English, Psychology, Religion, Philosophy and Literature, I don't even look at the clock and usually finish way before the time is up. With good scores, as well.
As for people who really do that well in tests. Doing well in tests doesn't mean anything. This is clearly shown by the fact that most people around 14 years of age cram for their tests by reading all of the text over and over again. Even if they do well in a test, it doesn't measure whether they've understood everything. It will then only measure how well they remember what they read. Which isn't what tests should be for.
Of course, there are always teachers who know this and therefore don't give grades based on only the facts and correctness of the written answers, but also based on evidence that the student has understood the topic. If they understood it, they will have examples and their way of explaining the topic will differ from the way it was presented in the text book.
Personally, I don't view people who do well in tests or get good grades as being smart or intelligent. The grade number alone doesn't tell me anything, as there are always at least two possibilities as to why they have that kind of a grade. Therefore, if I'm interested, I'll strike a casual conversation on the topic and see how well they answer. That is, how natural their answers are and how fast they come up with them.
Also, I don't like people who make a huge deal out of grades or test scores. For example, in my case, I've noticed that I get the best test results when I do my test in the afternoon. That is, I've done tests in the night, in the evening and in the morning. And none of those scores come close to the score I had when I did my test in the afternoon. This is especially easy for me to compare since I've done the same maths test around 23:00-2:30, 8:00-11:00 and 14:00-17:00. The result? 7/36, ~18/36 and 22.5/24, respectively. As you can see, the difference in the scores is huge. One of them is a failing grade, the other is an average one and the last one is a top-notch one. And yes, the test was from the same field, logarithms.
Smart is a funny word. It differs slightly from "intelligent", yet it doesn't equal "wise". Somehow, "smart" gives me an image of an activity of some kind. With it's obvious relation to "intelligent", maybe I could say that being smart is applying intelligence to every day activities?