Well, you're a magician. Right? How will you mix up the cards for performances? Shuffles! Cuts also work, but that's for another time. Here are some basic shuffles you'll need to know:
Overhand : Take the packet of cards and place them into your dominate hand(lefty or righty).
Then, pull off most of the deck leaving a few cards in your opposite hand. Then throw some cards off of it to the other pack. (you can also take some of the cards off with your opposite hand by using the thumb) Keep doing this until the cards are gone from your dominate hand to your opposite one, mixing up the cards quite well.
Riffle : Take the cards and divide it into two almost equal packs (close to 26 cards per pile). Then hold the packets in your two hands and have your thumb on top of the packets and your middles fingers on bottom with your pointers in the middle, bending the pack. then bring them close and let them fall from your thumb quickly. Try and make it go left right left right etc(or right left right left) so that it's mixed up well. then either push in the cards (easy way) as they are together like that and put your four fingers on each hand under the packs and your thumbs in the middle on top and bring up the packets(in a way where there is a hill facing up) and slowly let them fall into a neat pile. This will be easy to perform with some practice.
Chew on these for a while. Keep practicing them until they are perfected and I will teach you more later so that you know a variety.