I've been praticing....I really have been...

It takes practice, memorization, and a good healthy dose of intuition.

I can't, not matter how simple the cards are. Partly due to my short-term memory loss and partly due to whoever i'm giving the reading to, i allow them to choose which cards they want the reading from and they all pick different ones so i can never keep up.
There is one set i have memorized, but they are for my own personal use only :)

I personally found it more important to approach Tarot the following way:

1. Memorize some key meanings for the Major Arcana only but not go into this too deeply because I'd end up throwing those definitions out the window when doing an actual divination anyway..
2. Memorize astrological attributions including planetary and house meanings. Not only do these apply to each of the cards, the astrological and even climactic conditions at the time can influence how a card should be interpreted.
3. Memorize sephirotic attributions from the 'Etz Chayim (Tree of Life in Kabbalah) and the 4 Worlds (Planes of Existence) because Tarot is ordered accordingly. It's not just true for the Major Arcana, but also the Court Cards and Pips.
4. Spend time absorbing elemental aspects of the cards through ritual practice.
5. Incorporate use of the cards in pathworking using the energies of each card's image and their attributions as an axis for astral travel.
6. Incorporate cards into meditation and pathworking while solidifying connections with journaling.
7. I like to incorporate cards into hypnagogic dreamwork. Hypnagogic dreams are those dreams, usually of short duration, that occur just prior to Stage 1 sleep. If you use the card as a thought stimulus, the dream will answer in kind, providing insights out of the Unconscious. This practice also can provide a precursor to what's often described as "Sacred Sleep" in Wicca in which dream incubation manifests in dreams during REM sleep.
8. Consecrete the deck before divination and, while divining, let the cards speak to you as if you're lucidly observing a dream.
9. Be resigned to the fact that you'll probe with Tarot for the rest of your life because they're such an effective tool for this and none of us will ever exhaust their meanings.