Even if you don’t use a particular deck, there can still be useful information in a book about that deck that you can apply to other decks. For example, in The Ultimate Guide to the Thoth Tarot by Johannes Fieberg & Evelin Burger, they provide 10 Helpful Interpretation Tips. This one can easily be applied to any deck:
Every Single Symbol is Ambiguous
For example, let us consider the symbols Dove and Snake, both of which are counted among reoccurring tarot motifs. The dove is an attribute of different love and wisdom goddesses, the sign of the Holy Ghost, the peace dove, and a symbol of spirituality and sexuality. But also: it is the embodiment of aloofness, hysteria, and deafness. The snake warns of base urges and false instincts. However, the curled snake is also a symbol of higher development, of the wisdom of learning through experience. This is how it is with every detail in every card. Thus after many years, tarot card spreads are not boring, because one always discovers new meanings and symbols from the cards.