Don't concern yourself with getting hot levels during mixdown. Don't clip, don't come CLOSE to clipping if possible. If you come up with your absolute peaks at -3dB, that's more than wonderful if you're working with 24 bit audio. Don't limit, don't normalize, don't compress unless it's for the MIX - Not for sheer volume - If you want it louder, turn up the monitors.

Leave yourself some room for the mastering phase.

Obviously, I HIGHLY recommend not mastering your own mixes for more reasons than I could possibly have time for.

But that's for another thread...

...and don't touch the master fader.
Just leave it at 0db.

Do yourself a favor and don't try to master your own music... especially if this is your first time doing so. You're already totally unobjective, because it's your album, your music, your vocals and you're likely mixing the project in the same place where you recorded it. Mastering is not something you learn overnight. I personally highly recommend against it. There are legit mastering engineers for a reason. Check into Massive Master who answered above. His rates are decent and I'm sure he'll do a better job that you'll admit was well worth the (relatively) little money he charges.

If you want to start learning how to master stuff, do so with stuff that you're not releasing to the public... like music you made that you're archiving and just saving or demos that you're going to redo later. Don't try your first hand at mastering on a project that you're relasing to the public. It's plain suicide and will probably sound like a "demo."

My advice will probably come off as harsh, but I'd rather be the bad guy than tell you what you want to hear, only for you to learn a hard lesson after you butcher your tracks. Master is more than just putting a limiter in the chain and cranking the gain until it hits zero. Mastering is unbiased, objective advice with quality tools to preserve your master and make it better. If all to mastering was adding a limiter and a touch of EQ, a lot of "home mastering" projects would sound way better... but they don't so please take my advice.

Thank you Both!

Thank you both for your advice, and don't worry, I'm not thinking anybody is the bad guy. We all want honesty right? Well, basically, I'm wanting to start selling this album to the public to make some money to get it professionally mastered. Actually, I'm planning on putting more money into the album as far as taking it to a sound engineer to do the mixing, and then to a very well-known masterer for the type of music I do. His name is Rodney Mills, out of Atlanta, you may have heard of him. But for the time being, I want to make it as loud as I can with what I got without losing dynamics. The volume in the studio is fine. I just want it to be loud enough on the CD to where people don't have to turn it up another 5 notches in order to hear it like professional CDs. Thanks again! And God Bless You!

If you want to get it loud enough to sell enough so that you can afford professional mastering... maybe the best thing to do is EQ everything to taste and slap a limiter on it. The goal is getting everything to sound uniform and have the spectrum fairly flat... i.e. leave some room for folks to adjust their own EQs in their cars and stereos. I do understand your cash position, but I gotta keep it real on the "home mastering" issue.

Personally, I really like the Sonic Timeworks Mastering Limiter. You can demo it for 14 days. It is fabulous! Easy to use and is among the better sounding software limiters around. But with PT LE, I'm not sure you can use it (I recall it being a Direct X effect... though they may have an RTAS version). Check at http://www.sonictimeworks.com/

But seriously... get pro mastering as soon as you can afford it.

Would you recommend going ahead and paying an engineer to mix it before I have it mastered?

If you've got the cash and know someone good, it certainly wouldn't hurt - You can sit back and "produce" while the engineer is having a time. Always good to get an experienced set of ears at ANY stage.