Some people like to a tight slap-back Delay instead or in addition to reverb (it's all about what you like).
What we did in the old days (I haven't been in a recording studio in quite some time and I don't think any are even left standing anymore but...) doubling your vocals is always a good approach to "thicken" a vocal and was used extensively by groups like the Beatles to beef up vocals. You'd be surprised how hard it can be to sing a song exactly the same way twice but with a little practice, it is a great technique to make your voice sound fatter. (i.e., two tracks are better than one)
Bumping the EQ around the vocal range is also a good way to bring the vocals out of the mix a bit. As previous posters have said, it's an art to process vocals because each person's voice is different but singing in tune, doubling, adding some reverb and eq, and you should have something better than the original dry track that you started with. Experiment!
Singing in tune would be the first requirement. If your vocalist can't do that then you can use a tool like Melodyne Uno to correct the pitch. Once the vocals are in tune, a bit of Reverb always helps (gives you that great "singing in the shower" sound and we all know that we sound better in the shower).