Set all of the sliders on the equalizer to zero, which usually has a center detent. Move a slider up or down until you feel it stop, which will be a 0db setting for the frequency. This will allow you to hear the audio source without any alterations before you start to make any adjustments. If there is a master gain or volume, set this to zero as well.
Press the bypass button on the equalizer to make sure that no effects will be on for active listening. Like setting the sliders to zero, using bypass will allow you to quickly compare the original source material to the signal that has been adjusted with the equalizer. Most equalizers will have a bypass button for this purpose.
Turn on the audio track or recorded music you want to work with and listen carefully to the original source material. Press the bypass button after you have heard the original so you can use the equalizer. Listen to the overall bass frequencies of the material. Cut frequencies in the 250 Hz range to clear up the sound if it seems muddy, or boost the 100 Hz rage if the track lacks strength in the bass frequencies. Moving a slider down will lower a frequency, while pushing it up will increase the frequency.
Listen to the midrange presence of the material. If it is lacking mids, which would make the audio track sound hollow, increase them by pushing a slider up in the 500 Hz range. This will add midrange without cluttering the sound. If the material is heavy in midrange, or nasally sounding, lower the frequencies between 500 Hz and 1 kHz by a few decibels.
Make changes to the high end by adjusting the high end frequency sliders. Be careful because some of the frequencies may add a hiss to the sound. If the audio track lacks clarity, experiment with boosting frequencies along the 3 kHz to 6 kHz range. If the track is harsh in the high frequencies, cut sliders in the same range to tame them and smooth out the track.