I think you need to be in a certain kind of situation to go tall, and primarily that means you have an absolute shed load of food. No good going tall if you are on plains or in Jungle with no rivers around.
I still think tall is an inferior way of playing to wide though. I never seem to do as well at it.
I agree with the first sentence, "an absolute shed load of food" being a little bit exagerated, but there it is food is essential. As for the 2nd sentence for me it's exactly the opposite (much better tall vs wide...) ! And that's what's good in Civ : no definitive answer, not 1 way to play.
This being said, back on the subject. And back to the 1st point : food.
1st of all to grow an efficient tall empire you need food, and that's what you want to prioritize from turn 1 till humm... almost the end (of course situational exception always exists). And that has a direct effect on science as
is directly related to population. In that regard building a granary before a library will be better for example. Improve also the food tiles 1st,...
So try to make your cities as big and as quickly as possible (that's where those Tradition bonuses are important). It's the 1st point (and not only for science...).
And then I think you know the rest. Once you've launched the reproduction process for your citizens and filled their stomach, they'll be happy to do some research for you ! Build libraries and NC as soon as you can, caravans, beeline education, build universities, specialists (here again food is key...) and so on...