I've used cards myself too & I found the only way they "worked" was when I used my heart to discern amongst the pile of cards I had spread out & picked what I "felt" was right for the situation.
However when it came to interpretation it still was not completely helpful because the interpretations were very narrow sometimes I felt & did not express the situation even when later thought about. It was nice as a boost in terms of confirming what I already knew..but I sort of agree with Erin in that it's a tool but.. I guess it's like a computer. Good computer programmers can use any computer & function without one & do great work. Okay maybe a bad analogy but you get my point. Bad computer programmers can use a top of the line brand new ridiculous $6000 buck computer & still produce crud in terms of a product.
Tarot is nice & symbolic but.. as I've been studying more I have read that they say our words are symbols for the unseen & unknown. The symbols are symbols that stand for something we can only "know" through "understanding" or "being"...so it applies here. The tarot is symbolic for that which you could already "know" & if you try to put too much emphasis on the symbol there could be problematic interpretations much as some people have strange interpretations of "karma" & other symbolic words.