Working with a Tarot deck that you feel comfortable with will certainly increase the accuracy of interpretation, simply because you enjoy using the deck.
Choosing a Tarot deck off the rack of your local book store isn't a bad idea, but shopping around is certainly preferable. Perhaps check out some online stores for a deck that appeals to you. Remember, the Tarot works with your Inner Self, so if the deck doesn't appeal to you, there will be "resistance" during your readings. Bookstores, most often, can order any deck or set that you want; you simply need the name or the ISBN number that appears on the side of all books or boxes.
How much you enjoy the deck used builds the atmosphere of the reading. If you are comfortable with your deck, the questioner will be more comforatable with you, and the reading will go more smoothly.
So how do you know which deck is for you?
Easy. Flip through the catalogue or book shelves and when you get to a deck and say, "Wow! That's a pretty (or cool or whathaveyou) deck," that's the one for you! Yes, it's that simple.
Many go and buy the first deck they find, being only mildly happy with it, and then continue to search for a better deck. (I'm guilty of that.) Most of us don't have the money to purchase fifteen decks before settling on the right one. (No, I don't have the fundings either.) Taking the time to find one you want saves money and frustration -- the voice of experience here.