Amplify tracks - issue with different levels of recording

I am using:
Mac OS 10.8.5
Audacity 2.0.4, via the Installer
As will shortly be obvious, I don’t know much about working with audio though I am usually pretty good with computer stuff, so thank you for the help.

I recorded several tracks over two days. The second day the person whose singing I was recording held the mic to close. The first day’s tracks are on the soft side, the second day’s on the loud side; the tracks for the same day, though, are at about the same recorded volume. I will accept some of the distortion, but I want to bring the volume of the two days to about the same level.

Every time bring in a track, and pull up the Effect>Amplification, it seems to be at a different level. So, based on two test tracks, though initially I thought I would amplify the Day One tracks to 18db and reduce Day Two to -11, this doesn’t even work consistently on the same track. Now that I am totally confused, how do I accomplish the above goal (in bold) using no more than about 3 steps per track?

Thank you!

Try the Envelope tool
(but don’t go mad with it - it’s easy to get caught up in minuscule detail, when all you probably need to do is manage the extremes).

Thanks a million! Your post included the gain slider, which I had found and lost. Several people are depending on these tracks, so thanks from all of us! (And thanks for excusing my failure to find this stuff on my own due to my rush.)