What I have done to let the deck know who I am and that I am the reader is by doing readings. If it is truly your first time than do a bunch of random readings on yourself. It will give you an idea on how the cards work, how to read the cards, getting used to the feel of them, and let the cards know that this person will be user. If, however, you have dealt with tarot before than you can move straight to reading friends and family. Strangers will be discouraged at this time due to the unknown factor.
Using your deck for the first time can be a wonder and tricky because you are reading the energy off of the cards while understanding what each card means. For example, you get the fool and when you see the person you can tell they are scared and worried. With that information you can suggest to them that their journey is just started and that they should be more careful of where they step. It is harder to give an example but you will know what I am talking about when you do a reading. If not, than practice.