The first and most important thing to do is read your device's instruction manual and familiarize yourself with the recorder's functions and features, especially any that might be detrimental to the device's ability to pick up EVPs.

No matter what make and model of audio device you are using, you should avoid any 'noise reduction' or 'low cut' features, as these will automatically boost, alter, and manipulate the audio you are recording. It's a great feature if you're using the device for its intended purpose as a voice recorder, but not so much when researching EVPs.

You may also find that your device has an 'auto gain' feature turned on by default. This feature will automatically adjust the sensitivity of the microphone. If you shout into the recorder, it will dip the microphone to accommodate, but when recording in a silent situation, it will boost the gain on the microphone, pushing it...