I am far from being an expert, and I still have a long way to run regarding the tarot. This is merely a little bit of what I've learnt so far from what I've read on the subject, from other people's experiences, and from my own that is very limited yet.
There are several ways to read the tarot. I learnt to read the cards with a friend of mine, and after that I learnt another way. I've also learnt a third way with an aunt of mine. 
You should have your own deck and don't allow anyone else to use it, so that the other person's energy don't get mixed with your own and, subsequently, alter the readings.
I started out by using my sister's deck (she bought it and I used it. -lol-), but, as she decided to learn as well, I had to buy my own deck.
I currently own four tarot cards: my first tarot deck - the Fairy Tarot - and, a second one - the Egyptian Tarot. I also have an Art Noveau Tarot deck, and a Witch Tarot deck.
However there are a lot of other tarot decks - and, if you're planning on acquiring one, you should take your time to check them out and acquire the one you feel drawn to - it's the one that will work best for you.
I'm not on commission for this site -lol- but I like Lo Scarabeo's tarot decks. There are, of course, other places you can buy the decks, and you may even create your own. I'm not that creative, though. -hehehe-
Before you start using your deck - especially for the Wiccans: don't forget to bless it and ask for guidance for its use.
Make sure, before the readings, that you are focused on the reading, on what you wish to ask and the person you are asking for (even if it's you or if it relates to a third party) - visualization is very important - and that you are feeling peaceful and willing to help, otherwise you'll come up with a twisted outcome. While shuffling the cards, take your time to do so, until you feel it is enough - you'll be wrapping the cards in your energy and it's an important part of the process.
For those who might be wondering if I believe the tarot, my answer is: So far my readings have been correct. Of course you will only know if they are when things happen. On the other hand, the tarot doesn't show you the only future outcome, but a possible one - sometimes I wish my readings were wrong.
And keep in mind that the cards sometimes have a mind of their own - you ask them one thing and they will give you an answer to another problem in your life, even if you really don't care about it at the moment. -lol- A friend of mine asked me about her love life and the answer was all about her work life: about a job that would come up and make her smile. Oh, the job did come up and she is happy with the result. 
Another thing you can do: in the beginning of your day, shuffle the deck, draw one card and see what it means. Throughout your day see if/how it applies. It will help you to become familiar with the cards and develop your sensitivity to them, as well as your intuition, which is also very important.
Also, keep a journal with your readings, apart from your book of shadows and your dream journal - if you have one (also helps you to develop your intuition).
