You won't find one single answer to that. There are lots of traditions. Italian and French Marseille practices go back to the 1400s, and people read in so many different ways. Some mix astrology, psychic work, guides, or energies with tarot. Jungians take a psychological tack. Others use therapy-style readings, and some tell stories. That's just scratching the surface.
Dad was right in the end: don't lean on the book while you're reading. That doesn't mean you shouldn't know the book. Learn it, then be able to read without it. For me it's like having a stream nearby you can dip into while you listen to what the seeker is saying.
Imagine a conversation between the seeker, you, and the cards. The cards don't speak by themselves, so you have to give them a voice. The seeker has to ask or say something for the cards to answer, and that can go a thousand different ways. The more you know the books, the more likely it is that "the cards" — really, you — will have something useful to say.
I read with a French Tarot de Marseille deck. I'm not great with RWS decks. The Marseille pictures are vague enough that I can lay them out like a comic strip sometimes. Lines, colors, repeating shapes, similar icons, or a line that runs through several cards — those things start to mean things for me. Seeing how cards interact sparks new questions and often pushes me to refine or completely rethink an idea.
When you look at a spread, try making it a habit to imagine the cards talking to each other. Put your attention in the gaps between them and let the seeker's question sit in that conversation. Reading books adds to the pool you draw from. Then your gut wakes up and starts to have its own take.
Pictures don't mean anything until someone asks, shuffles, and draws. Still, it's useful to think about the cards philosophically. Think about The Fool — how do freedom and stability sit together? Or how does The Magician show both a false sense of control and a readiness to let things unfold? The Papesse holds faith and doubt side by side, the holy and the everyday.
That’s different from just memorizing a card meaning. I think of L'Hermite as a wise, probably older person who withdraws to seek truth, practice silence, and reflect. That gets me the ideas of truth, silence, seeking, austerity. Great. But when you really look, the monk has a lamp. Why? Is it only because it's dark, or because the lamp itself points to both darkness and light? L'Hermite balances wanting to know with being okay not knowing. The Magician, card I, starts the sequence; L'Hermite, card VIIII, lets go of dreams and embraces what is. As he seeks truth, he can show both old knowledge and a kind of childlike innocence, like The Fool. Once you understand a card as a personality, a lot opens up.
Those who work more with the RWS system will have more to add than I do.
Be careful!