Mainstream academics is mostly about reading books, but wisdom is more than that. I say that as a very avid reader myself. You have to read critically, but not dismissive. Let it sink in and entertain ideas, but still be courageous enough to throw some groundbreaking philosopher with an IQ of 150 into the corner because you think he's wrong. That's far more important than remembering every small little detail of some philosophy or concept, but it doesn't lend itself to standardized testing. Qualitative testing, meanwhile, all too easily ends in selection pressure for indoctrinated sycophants.
Also important is learning about different disciplines and schools of thought. That can prevent your thinking from becoming schematic. Your different modes of thinking will also inform you of flaws in either mode. Your inner historian might revolt at a bad example given for an economic theory you subscribe to, for example, and this kind of conflict can be very illuminating.
Experiences also play a role. You have to fall in love, get into fistfights, support a family, travel, work out for some time, etc. etc. In all that, you must keep your abstract thinking at hand, but without getting oblivious to practical results. There's no schematic way to dealing with this. You cannot just subordinate your ethical theory to your whims, for example, but when you consistently detect conflicts between your intuitive sense of what's right or wrong and your rational judgement, then you will have to reconcile that conflict in some way. Street smarts should not be overrated, however. Epxeriences give potential, they're not a vaccine against shitty opinions. You'll find people with a very moving life who nevertheless hold retarded opinions, demonstrating once more that experiences are not determinants of our future, how we react to them is.
If all this sounds vague, demanding and complicated, well, that's why one in ten thousand has what it takes to be a true intellectual, and that's a generous estimate. Ask yourself how many "intellectuals" nowadays are truly wise, and how many are pampered kids that aced an institution in which originality and critical thinking took second place to memorizing facts.