what meshuggah said plus-
don't boost over 3db on any freq.
cut more than boost if you have to do a lot of eq.
don't go overboard when adding high end eq.
if you're having to add a lot of highs, try tracking without a pop filter, using it only during the troublesome parts. that's how i do it at least.
if your reverb gives you access to a lot of settings, play with it to get the best sound for the voice you're mixing. don't settle for presets. if you don't know what each knob does, do a little search so you know what you're doing. don't just turn the knobs.
if you're doing a ballad, you can get away with longer reverbs, if the songs is fast tempo you should stick with shorter reverbs.
i really like to compress vocals, so i always do it, even if just a little bit. if you're going to do it, do it during mixing, not tracking.