Record them Crisp and clear. Sorry, that is the only way. I'm not sure what you mean, tho, it could be all kinds of things. It would help if you would list your equipment, post the song or just your vocal so we could understand the problem.
Performance, room, mic, preamp and then fix in the mix.
If you are stuck w/ what you've recorded there are a couple of things. One, if you want clear vocals they have to be louder than anything else going when they do, and there shouldn't be any music lines masking the main frequencies of the voice (you don't want flutes playing over a delicate voiced female, or a fast bass line playing over Barry White). Usually a compressor goes on the vocal to ... compress the difference between the loudest and quietest part of the singing, making the whole vocal track closer to the same volume. EQ. And finally don't slather on reverb and other effects until you get the vocals close to the right sound and volume.
Welcome to mixing. It is an art, it is a science and it takes a while to learn, because you have to do and figure out your own "sound."
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