I'm going to disagree a bit on methods. Having taught and performed for decades, mostly classical guitar, I feel that Christopher Berg's Mastering Guitar Technique: Process and Essence is the best single book available. He has studied all the old masters: Carulli, Crcassi, Sor, Aguado, etc., and was a student of Aaron Shearer's as well. This little book from Mel Bay is ideal for someone like the OP, who can read and conceptualize, but it really gets into the nuts and bolts of good technique and tone, utilizing the latest research into avoiding injuries as well. A careful reading of the text along with patient and mindful practicing of what's in this book will give you a strong foundation for pursuing music you want to play on the classical guitar.