Some hints on using Audacity to tweak your ringtones:
1) After cropping down to just the audio you want, Normalize (
Effect, Normalize) the audio to 0 db. This will raise the overall volume of the clip, and will help dramatically for quieter audio. If your audio clip changes volume significantly, you may wish to play with the
Leveler, or
Compressor effects to help adjust it to your liking.
2) To give your clip a professional touch, select a small section at the beginning of the track and chose
Effect, Fade In. Then select a small section at the end of the track, and choose
Effect, Fade Out. This will give you a smoother sounding tone, so that it doesn't start and stop abruptly. The amount of audio you select determines how slow it fades in or out.
3)
And to be a good citizen, export your file as an .ogg, instead of an .mp3, and support open formats! 