Professional mastering services will clean up your audio, send it through a compressor and increase the volume to improve the overall sound. Most of these steps can be completed at home with the use of a free audio editor called Audacity. If your goal is to simply improve the sound of the audio file, then there are only a few basic functions you should be concerned with. Learning how to make songs better with Audacity only takes a few minutes with the right knowledge.
Open Audacity and drag the song you wish to edit into the audio editor. This will start the process of importing your song and preparing it for mastering.
Click the "Effect" menu and then select "High Pass Filter." A high pass filter will remove any artefacts that are below a certain frequency. Enter the value 192 in the Cutoff frequency. This will remove any frequencies below the 192 Hertz value and should reduce unwanted thumbs and bumps.
Select "Normalize" from the "Effect" menu. Don't modify any of the values and press "OK." This will increase the volume of your recording without clipping.
Select "Compressor" from the "Effect" menu. Don't change any of the settings and simply click "OK." This option will compact the audio and help to give it more presence. Professional studios will send a final recording through several compressors.
Don't use headphones to monitor your song. When editing audio, sometimes loud artefacts are entered into the file. This can damage your hearing if you have the volume on high and earphones on.