Dovetail false shuffling
You need to divide all the cards in half and then shot the cards at the ends. By this you will be able to use false shuffling technique or the Dovetail false shuffling.
Keep the top card in place
In order to keep the top card in place, you need to shuffle the deck of cards as you normally do. However, you need to check that the last card to lie is your top card. In case you want more than one card to stay in a place, it is advisable for you to make the upper half of the deck larger than the lower. By this you will riffle the lower half of the cards before reaching the top half.
Let the card fall first
In order to keep bottom cards on their position, you need to let them fall first. Then you need to combine these steps in order to keep both top and bottom cards in place.
First you need to keep the top half of the cards smaller as compared to the bottom half. Then you need to shuffle but only from the corners of the cards. It should end in a way that smaller half of the cards come on the top.
Now you need to bring your fingers together to show others that you are finishing the shuffling. Then you need to hold the larger half. In the end you need to slide the upper half of the deck back on the top.