Which tree?
I'm not even sure we're answering Paranfer's question. After re-reading his original post a few times, I don't see any reference anywhere to prepping his recording for a mastering house. The only time he used the word "mastering" was in the phrase "mastering cd" in the thread title. I think he is just burning his "final" CD and is disappointed that it doesn't sound as loud as commercial releases.
Paranfer, if my above analysis is correct, what you need to look at in "mastering" your own CD (I'll define that here in this context as the things you do to "finish" the recording after you have mixed down to stereo and before you push the "Burn" button) is some kind of dynamic compression via either manual peak editing or via a compressor.
The idea is to decrease the volume difference between the loudest peaks in your stereo mixdown and the "average volume" or RMS volume of your recording. By reducing the size of the peaks, you are giving yourself more "headroom" to be able to bring up the overall volume of the mix before/without hitting zero on the digital meters.
There is a whole lot of talk about the use of compressors and limiters - both plug-ins and outboard - for this task, and they indeed work great when used properly. There are times, though - for example if the type of compressor you have just does not have the right "sound" for the type of music, or if you just can't afford the "good stuff right now", or if you're just learning how to use compression but you're on a deadline to press the CD and don't have the time to experiment - when you can get a good overall volume increase in your master through "manual compression".
The idea there is to just use your favorite waveform editor to zoom in on the largest, most obvious transient peaks in your stereo mix. Depending on the recordings and the type of music, there may be only a handful that rise blatently above most of the rest of the recording. Zoom in on those blatent peaks, highlight them with the ends of the highlighted areas corresponding to the basees of the peak, and drop the volume by a however many dB necessary to make them more in line with the average peaks in the rest of the song.
Once you have "ironed out" only the worst offenders, then measure the volume of the highest peak in the song (most editors will calculate this for you somewhere.) Then increase the overall volume - not with normalization, but with simple volume - of the song by just under that amount. For example, if your highest peak come in at -5.2dB, you might want to boost your volume at that point by 5.0dB or so. This will give you a 5.0dB boost in the overall volume of your mix without clipping and without the need for tools which might not be at your disposal.
Using this method I have found that I can often get as much as 3-6 extra decibles of headroom to play with without artifacting the sound by running it through extra plugins.
Of course if you have a good limiter or compressor that you know how to use properly, or if you song has such extreme dynamic range that you have hundreds of wild peaks that need to be tamed, then you're better off using those tools instead of doing it manually. Plus sometimes a compressor may add a particular sound (many times people call it "warmth") that you just don't get otherwise, in which case just running it through the extra circuitry enhances the result.
But I just wanted to illustrate the options; there is always more than one way to skin a cat, and not all of them necessarily mean using more gear.
G.
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