Next, open up Audacity and click the effects tab. A drop down menu will pop up. From the drop down menu, find the setting called "normalize". Click normalize and a small window should pop up. It will give you the options to how much you want to normalize. The best setting for this is between -9.0 and -15.0. If these levels don't fit your needs, adjust until you get the desired level and click "ok". The waves should now appear smaller than they first did when you imported the song into Audacity.
Now to boost the song, click the effects tab again and click the "Bass and Treble" setting. This will open up another smaller window in Audacity giving the options to adjust the bass and treble levels. Keep the treble at zero and adjust the bass until it fits your needs. You can always click the preview button to make sure your'e satisfied and then click "ok".