Did you test your setup with the nRF24L01 basic tutorial here:
If so, did the example code work in SimpleTx and SimpleRx work correctly for you?
Are you using the nRF24L01+LNA+PA device with the small external aerial? If so, they require more power than the basic nRF24L01 board does.
Also, with max power set, you need to separate your Rx & Tx by a few feet when testing on the bench.
Please provide a drawing of how you have connected the various parts of your project together. (Hand drawn and photographed is fine.)
Also please tell us which Arduino you are using for the Tx and which Arduino you are using for the Rx.
And finally, please tell us what power source you are using for your Tx and Rx systems.