Open the audio file containing the vocal performance in Audacity.
Click "Effect" and select "Compressor." Adjust the settings on the "Compressor" control panel to bring the waveform's peaks and troughs closer together. This will create more consistent-sounding audio.
Click "Effect" and select "Equalization." Apply a high-pass filter to the track and set the frequency cutoff at 150Hz. This will enhance clarity by eliminating unusable low frequency rumble from the vocal track.
Click the track to highlight the audio, click "Edit" and select "Duplicate." Click and drag the duplicated audio to offset it from the original track. This will create the illusion of a layered or multitracked vocal performance and will give the vocals extra body.
Press "Play" on the transport bar to listen to the vocal performance.