Here is an article about mixing, typically a topic more associated with music recording than voice over recording, but a fundamental topic in audio recording if you're doing music.
However, understanding how to mix and generally play around in multitrack recording software can still be important for certain kinds of voice over jobs. For instance, I do a monthly e-learning voice over job that that has lots of phrases alternating between male and female voices (yeah, me and my wife:), with 3 seconds between them. I use the holy heck out of my mixing/multi-track recording skills to make this workflow fast and easy. For example, I put all the lady parts on one track and all the guy parts on another. Then I split the phrases on each track and color-code them (yes, blue for boys and pink for girls:)). Then I space them out with like 7 seconds between them. Then I off-set one track so I can just select all the parts on one track and drag them up to the top track so that all the parts are on one track. The colors help me make sure it's boy-girl-boy-girl, etc. Then I simply select all the parts and tell the track I want them spaced exactly 3 seconds apart. Try doing THAT in a plain old editor:).
Anyway, check this article out, even though it's mostly to do with music. You might learn something applicable to both music and voice over recording.
See the article here: