MicrophoneDouble-tracking a vocal is a tried and true technique for adding character to (or covering flaws in) a vocal track. Here are two threads from homerecording.com on doubling vocals: [Thread 1], [Thread 2]:

Double tracking really depends on the vocalist being in control of his/her performance. Some people are good at it and some people aren’t. Doing it line by line does help. (sing the line, then sing the line again, then move on to the next line)

Sometimes you have to edit the hard consonants (T’s, K’s etc…) off of one of the takes.

You could also try to put the second take quieter in the mix.

And another that could come in handy if you need to record group vocals with limited or minimal equipment:

Set up your monitors or some speakers in the recording space such that everybody could hear the tune and sing along without headphones. Set up your mic, set the levels, etc. Have everybody leave the room and record just the music the way the vocal mic would hear it blasting from the speaker – what would be the monitor “bleed” into the vocal mic. Now, have everybody come in and do the vocal part on a different track without changing a thing.

At this point you should have two tracks – one with vocals and the music bleeding into the mic, and another with just the music bleeding into the mic. In theory, if you mix these two together to another track while reversing the phase of one of them, the music bleed should cancel, leaving you with just the backing vocals.

Here’s a Gearslutz discussion on working with a singer who sucks:

if the “technicals” are lacking, then it’s time to pile on the character.

For me, I find that overdriving and overcompressing … adds tons of character to a sound, especially thin vocals.

Also, I like using a bandpass filter, this makes the midrange more present, upfront and in-your-face.

And finally, some pros share their thoughts on manual de-essing, i.e. riding the fader or using volume automation to reduce the volume of a vocal only on the sibilants, rather than using a compressor or de-esser tool:

De-essing by hand is by far the best way to accomplish a good result, albeit the most time intensive.

But two things to remember:

1) In many instances, the sibilance may actually be caused by the use of a pop filter. Certain types may cause comb filtering that enhances some offensive freq’s, while reducing others you may need or want.

2) At times, what sounds to be sibilance may actually be the lack of a part of the high frequency spectrum, rather than the excess of same. In these cases, the application of an extremely narrow band of the missing frequency may make things “normal” again. But in most of these cases, one really needs to both add the missing freq, and gently reduce the overall high freq area.