MP3 CD Burner has a "normalization" option that will try to even out the volume levels of a group of songs. In MP3 CD Burner, click on the File menu and select Preferences. In the Audio Processing preferences, you'll find an option called "Normalize track volume if volume level is X % different than..." If you find that the normalization isn't working the way you want, you can try changing this setting to "maximum level." Finally, the auto normalization setting isn't perfect and it doesn't work well on some songs. In these cases, just right-click on the songs in the MP3 CD Burner song list and manually adjust the track volume.
In addition, you can try "Boosting" a song which will bring up a song"s percieved loudness. Right click on a track in the song list and select "Adjust Volume/EQ/Boost". Click on "Use Boost" and increase the settings if desired.