Listen to your vocals with no music. Before you can properly mix you have to listen to the performance. Gently fade out any pops or unwanted breaths you hear in the performance.
Add equalization to your recorded vocals. EQ helps the voice sit better in the mix and removes unwanted frequencies from the performance. You can also use it to add a deliberate effect to the vocals. In general, lightly boost up the 6kHz region to add presence -- be careful, however; overdoing it will add sibilance. To reduce popping "P's" and "T's," cut everything underneath 80Hz.
Add compression to the vocals. A compressor balances out the dynamic range of the vocal performance while lowering the highest volume peaks. Overall, this makes the vocals seem more controlled and natural in the mix. Experiment with different compression settings, depending on the specific vocal performance. To start, try a 2-to-1 ratio with a 5 millisecond (ms) attack time and a release time of 50 ms. Gradually adjust the compression settings until the vocals sound the way you want. Keep in mind, over-compressing your vocals will kill the emotion and make the performance sound dead.
Pan your vocals creatively. For advanced mixers, panning is a great tool to give the vocals more depth and space in a mix. In general, your lead vocal take should be in the center and not panned. Ad-libs and choruses, however, can be panned to your desire and make your vocals sound bigger in the song.
Add a little bit of spatial reverb or simple delay. These effects make the vocals sound like they were recorded in a natural environment as opposed to a "dead" room. Too much reverb will make your vocals sound distant and thin though. Try using a plate reverb on your vocals with pre-delay of 30 to 50 ms. Adjust the settings until your vocals sound the way you want.