(Taken from another post I commented on.)
With any reading you do there are many factors that come into play. The question in mind, if there is a question; the position the cards lay, normal or in reverse; what each individual card placement means, what the colours of the cards tell you; what the pictures tell you; the meanings to each card whether normal or in reverse position; how the cards interact with each other; and what the cards tell you. There may be more, but that's a general outlining of the reading.
When doing a reading, there a couple different ways it can be done. This is a matter of who does the shuffling of the cards. 1) If you have the querent in front of you have him/her (as is suggested) shuffle the deck as they focus on the matter they want their reading to be for. When they feel that they are ready they should place the cards down and cut the deck. (Cutting of the deck is optional). The tarot reader then takes the cards, keeping a clear mind, places the cards appropriately drawing one card at a time from the top of the deck with the faces down. And from there interpret the cards. 2) Whether the querent be in front of you or some distance away, focus only on the question and/or the querent as you - the tarot reader - shuffle the deck until you feel ready to place the cards. Cut the deck - again, an optional step. Place the cards in the same manner as stated in example 1. And interpret.
Some times when shuffling the deck you may have a card that just seems to "jump out." These cards that jump out are believed to be important to the reading to be given. When implementing them you should keep the card to the sideline and read the card last, after the spread as been interpreted. They are said to help give better insight to certain parts of the reading or as a whole. If you choose not to do so, simply place the card back in the deck and resume shuffling.
At times you may have a card, section, or what have you that may not make sense or be completely clear. For this what you can do is, (after all cards have been placed and interpreted) draw a single card from the top of the face-down deck to be interpreted with the reading as a whole, with the unclear section, or with the individual card that is not clear.
Overall, take what's there and practice. Eventually you will find a method that works for you as you further your readings and skills through practice.