You may also want to add a small amount of reverb (echo) this is used in recordings to "Fatten out the sound".
If vocals and backing track are seperate then it is a simple process to add this to your voices before mixing down to a finished track you can add to your video.
I personally work on vocals seperately and "slot them in" the music or whatever other tracks you are using.
Note: don't overdo it - your vocals will become muddy.