Open the digital audio file in your recording program. Isolate the vocal track, and remove any noises at the beginning and end of the track. Zoom in on the vocal track, and remove any extraneous noises in between the vocals.
Fade the vocals in at the beginning of the track, and out at the end of the track. Choose a hi-pass/low-cut filter to remove high- and low-end frequencies from the track. Choose a filter of 80 to 150 Hz depending on the amount of high- and low-end noise present in the recording.
Add compression to the vocal track. Compression allows a vocal performance to blend with the other audio present in the recording. Add compression at a ratio of 8 to 1. The compression also will round out peaks in the vocal performance.
Add compression again to round out the sound of the vocals, this time at a ratio of 1 to 5 or 2 to 1. Compression also works to make the voice sound well-rounded and stable.
Go back and listen to the track with the compression. Adjust the volume in areas of the performance that are too loud or too quiet. The volume of the voice should be even throughout the performance.
Equalize the vocal track at 6 decibels or less. Equalizing the track will allow you to add or remove frequencies. Adjust the highs, mid-range and low frequencies to create an even and warm tone in the vocal performance.
Add the desired effects to the vocal performance, such as reverb. When adding effects, remember that less is more. Add reverb and other effects in small, tasteful amounts. Too many effects can work against the quality of the recording.
Go back and listen to the entire vocal performance. Make revisions and adjustments as needed. It is best to listen to the track through different speakers -- such as your computer, car and stereo -- to hear the true quality of your mixing.