First select the entire track holding down your "ctrl" button, then press the letter "A". You should now have your screen looking somewhat like this. (never mind my colour scheme from Mars).
Go to the process menu, then click on normalise, You can set the peak to 0db (100%), but I prefer to set it to -0.07db (99.20%). I always like leaving a buffer for making absolutely sure, that they will be no distortion.
Click OK and then the size of your wave-form should increase.
Remember before saving, if you are unhappy with any of the processes that you have made so far, you can simply undo them by going to the edit menu, and selecting "undo".
To finish off, go to file, then save. This track is now ready to burn to CD.