The worst thing you can do is change the meanings of the cards with each reading because you’ve just read a new book on the subject. Sometimes the meanings will change slightly in relation to the other cards, but use your own intuition for this, not the guidance of someone else’s opinion.
The cards work through you not the writer of a tarot guide. It is very important to establish an ongoing meaning for the cards for them to work properly.
Let’s take The Fool for example. Here are a few meanings from different books.
Innocence, risk taking, new adventures, foolishness
A trusting nature, seeking answers to hidden messages, unconventional, a need to be carefree, spontaneous
Courageous, optimistic, having faith in self, listening to our inner self, leaping into a new phase of life
An innocent and daring personality
A beginning of a journey, a leap into the unknown, a new chance, an important decision, time for a change, purity of action, being born again, all things are possible, trust in a higher power, an unexpected influence
And the suggestions go on and on. Try to remember all of this and you are going to end up with either a headache or a puzzling reading.
Do yourself a favor. Pick two key words, stick to them, and wrap your intuition around developing a full-fledge interpretation at the time of the reading. Make yourself a journal and use it as a guide if you need one rather than searching through your various guidebooks.