I'm very suspicious of the notion that there is some raw quality of someone's mind that makes them smart - as if most people are born with some innate intelligent quotient. I do agree that some folks are just very smart, and some undoubtedly are, but the vast majority of us "learn" to be smart, if that makes sense. It's a combination of factors - biological (your DNA), social (your upbringing) and what education you had access to (good schools, good teachers, and parents who care about your education). Also, it's important to note that having had access to good nutrition as a child is crucial to developing intelligence, since so much of the brain's development happens at a very early age.
Standardized tests gauge your acuity at taking standardized tests, some of which require certain skills that some people may or may not be strong with. That's all. I think the generalized notion of "intelligence" is far too vague to quantify with any sort of test, no matter how cleverly designed.