If you read and, closely, follow Robin2's simple rf24 tutorial you should be able to get them working. That tutorial sure helped me. Run the CheckConnection.ino (look in reply #30) to verify wiring between the radio module and its processor (Arduino).
Make sure the rf24 power supply can provide enough current. I use homemade adapters like these. They are powered by 5V and have a 3.3V regulator on the board.
If using the high powered radios make sure to separate them by a few meters. The may not work too close together.
Reset the radios by cycling power to them after uploading new code. I have found that to help. They do not reset with the Arduino.